All Calculators
Long Divide,Multiply, Add and Subtract Calculator
Long calculator is the best assistant in your studies. The calculator can long add, long subtract, long multiply and long divide examples, as they teach in school.
Converting a Number from One Base to Another
The calculator converts numbers and shows the solution. Converting numbers between number systems. Detailed answer with solution.
Numeral System Calculator
This online calculator is designed for addition, subtraction, multiplication and division of numbers written in binary, ternary, octal, hexadecimal and any other number system. Fractional numbers are supported. Long division.
Long Binary Calculator
With this calculator you can perform long addition, subtraction, multiplication or division of two binary numbers
Long Multiplication Calculator
This calculator can multiply two numbers long. You can multiply integers and fractions, positive and negative.
Long Division Calculator
The calculator will divide any two numbers (positive or negative, integer or decimal), with steps shown. Enter the dividend and the divisor and get the quotient to the given precision without remainder or quotient with remainder.
Fraction Calculator With Step-by-Step Solution
The online fraction calculator allows you to perform basic operations with fractions: addition, subtraction, multiplication and division. As well as reduction, reduction to a common denominator and simplification.
Right Triangle Calculator
The right triangle calculator allows you to calculate the basic parameters of a triangle, such as side lengths, area and perimeter, knowing some of them.
Long Subtraction Calculator
The Long Subtraction Calculator is a tool designed to perform subtraction using a classic method known as "long subtraction". This method allows users to perform subtraction of large numbers by organizing the process in columns, making it more visual and understandable.
Percentage Calculator
The percentage calculator finds a percentage of a number, adds and subtracts percentages, finds 100%, calculates the percentage ratio of two numbers and other operations with percentages.
Long Addition Calculator
Long column addition calculator. Online calculation with detailed step-by-step description of the algorithm.
Megabits to Megabytes
Data unit converter: bits, bytes, kB, MB, GB, TB, megabits and gigabits, decimal and binary (KiB, MiB, GiB). File download time from internet speed.
Comparing Fractions Calculator
Calculator for comparing two fractions. Allows you to determine which of two fractions is larger, which is smaller, or maybe they are equal.
Number to Words
Write a number in English words — cardinal, ordinal and check format — and in Russian in any case, including amounts in rubles.
Blood Type Calculator
Which blood types and Rh factors a child can have given the parents' blood types, the probability of each, and possible blood types of the father.
Add Percentage to a Number
The calculator adds a given percentage to any number with a step-by-step solution.
Russian Plural Forms
The correct form of a Russian noun after a number (1 яблоко, 2 яблока, 5 яблок), with the rule and a table of forms.
Mass Fraction of Element
Find the mass fraction (mass percent) of an element in a compound and the mass of the element in a sample, with a solution.
Length
Length converter: mm, cm, m, km, inches, feet, yards, miles and nautical miles. Exact conversion with a solution and a table of all units.
Time
Time converter: seconds, minutes, hours, days, weeks, months, years and milliseconds, with a solution and a split into h, min, s.
Volume
Volume converter: mL, cm³, liters, m³, US and imperial gallons, pints, quarts, fluid ounces, barrels and cubic feet.
Area
Area converter: mm², cm², m², km², ares, hectares, acres, square feet and square miles. Conversion with a solution.
Mass
Mass and weight converter: mg, g, kg, tonnes, carats, ounces, pounds, stones and tons. Exact conversion with a solution.
Speed
Speed converter: km/h to m/s and back, mph, knots, feet per second and the speed of light, with a solution.
Complex Numbers
Complex number calculator: addition, multiplication, division, modulus and argument, polar and exponential forms, De Moivre powers and roots.
Time Zones
Convert time between cities with daylight saving time, find local solar time by longitude (15° = 1 hour) and the time zone number.
GCD and LCM
Calculator for finding the greatest common divisor (GCD) and least common multiple (LCM) with a step-by-step solution. Up to 50 numbers at once.
Vector Operations
Add and subtract vectors, multiply a vector by a number and find a linear combination of vectors from coordinates with a step-by-step solution.
Integral Calculator
Integral calculator: indefinite integrals by the table, by parts and partial fractions; definite integrals by the Newton–Leibniz formula with the area shaded.
Punnett Square
A Punnett square from the parents' genotypes: gametes, genotypic and phenotypic ratios, monohybrid, dihybrid and trihybrid crosses, sex-linked inheritance.
Permutations and Combinations
Combinatorics calculator: the number of permutations, arrangements (nPr) and combinations (nCr), with and without repetition, with formula and solution.
Accelerated Motion
Kinematic equations: v = v₀ + at, s = v₀t + at²/2, acceleration and time, free fall and vertical throw.
Ohm's Law
Ohm's law I = V / R: find current, voltage, resistance and power P = V · I = I²R = V²/R with unit conversion and a solution.
Limit Calculator
Find the limit of a function at a point and at infinity: indeterminate forms, L'Hôpital's rule, notable limits and one-sided limits.
Oxidation States
Find the oxidation states of all elements in a compound or ion with a step-by-step solution.
Derivative Calculator
Differentiate any function with the rules shown step by step, the derivative at a point, the tangent line, the second derivative and a graph.
Triangle Area
Find the area of a triangle from the base and height, three sides (Heron's formula), two sides and the included angle, a side and two angles, for equilateral and right triangles.
Vector Magnitude
Find the length (magnitude) of a vector from its coordinates or from two points in 2D and 3D, the unit vector and direction cosines. Exact answer with roots.
Square
Find the area, perimeter, diagonal, inradius and circumradius of a square from its side, diagonal, perimeter or area.
Rectangle
Find the sides, area, perimeter, diagonal and angle between the diagonals of a rectangle from two sides, a side and the diagonal, or the perimeter and area.
Sunrise and Sunset
Sunrise and sunset times, solar noon, day length and civil twilight for a city or coordinates on any date.
Energy
Energy calculator: kinetic E = mv²/2 and potential E = mgh, plus speed, mass and height from energy, with a solution.
Inverse Matrix
Find the inverse of a matrix by Gauss–Jordan elimination or the adjugate method with a detailed solution and a check; the answer in fractions.
Equation Balancer
Balance chemical equations online with a step-by-step solution and the electron balance for redox reactions.
Power
Power P = W / t and P = F · v: find power, work, time, force or speed with conversion of kW, hp and kWh and a solution.
Prime Factorization
The calculator quickly breaks any natural number into a product of prime factors with a step-by-step solution. Up to 50 numbers at once.
Rhombus
Find the area, perimeter, diagonals, angles, height and inradius of a rhombus from a side and angle, the diagonals or a side and height.
Map Scale
Map scale calculator: real distance from the map, map distance from the real one, and the scale from two distances.
Determinant
Find the determinant of a matrix up to 6×6 by Gaussian elimination or cofactor expansion, with the rule of Sarrus for 3×3 and a detailed solution.
Molar Mass
Find the molar mass of a compound from its formula (H2SO4, Ca(OH)2, CuSO4·5H2O) with a step-by-step solution and mass fractions.
Mean
Find the arithmetic, weighted, geometric and harmonic mean of numbers with a step-by-step solution. Exact answer in fractions.
Trapezoid
Find the area, height, midsegment, perimeter and angles of a trapezoid from the bases and height, all four sides, or for an isosceles trapezoid.
Circle
Find the area and circumference of a circle from the radius, diameter, circumference or area, and the area of an annulus. Exact answer in terms of π.
Triangle Calculator
Solve a triangle from SSS, SAS, ASA, AAS or SSA: law of sines and law of cosines, all angles, heights, medians, bisectors, radii and an existence check.
Distance from a Point to a Line
Find the distance from a point to a line in 2D and 3D and from a point to a plane, with the foot of the perpendicular and a step-by-step solution.
Solubility Table
Solubility table of salts, acids and bases in water: formula and name of a compound from its ions and its solubility.
Midpoint
Find the midpoint of a segment, the point dividing a segment in a given ratio and the endpoint from the midpoint in 2D and 3D.
Temperature
Temperature converter: Celsius, Fahrenheit, Kelvin, Rankine and Réaumur. Conversion formulas with the numbers substituted.
Parallelogram
Find the area, perimeter, diagonals, heights and angles of a parallelogram from a side and height, two sides and an angle, or the diagonals and angle.
Inequalities
Solves linear, quadratic, rational, exponential, logarithmic, trigonometric, compound and numeric inequalities, and those with absolute values and roots.
Regular Polygon
Find the side, area, perimeter, radii, interior angle and number of diagonals of a regular polygon from the number of sides and one value.
Altitude Temperature and Pressure
Temperature change with altitude (6 °C per km) and air pressure change (1 mmHg per 10.5 m): geography problems with solutions.
Huffman and Fano Codes
Check the prefix (Fano) condition, build a Huffman code, check unique decodability and find the shortest code for a new letter.
Find 100 Percent
The calculator finds 100% if a number and its percentage are known.
Distance by Coordinates
Distance between cities and points by latitude and longitude along the great circle, and along a meridian or parallel.
Kepler's Third Law
Orbital period from the semi-major axis and back, comparing orbits, and satellite periods by Kepler's third law.
Cross Product
Find the cross product via a determinant, the area of a parallelogram and a triangle, the scalar triple product and the volume of a tetrahedron from coordinates.
Add to Date
Add or subtract days, weeks, months and years from a date. The result with the day of the week, a solution and a calendar.
Gas Density
Relative density of a gas to hydrogen, air or oxygen, density at STP and molar mass of a gas, with a solution.
Azimuth
Compass direction from an azimuth and back, back azimuth, true azimuth from magnetic, azimuth between two points.
Subnet Calculator
Network and broadcast addresses and the number of hosts from an IP and mask, a mask for a number of hosts, possible masks.
Half-Life
Radioactive decay N = N₀·2^(−t/T): amount remaining, decay time and half-life.
Sun Height
The Sun's height above the horizon at noon at any latitude on equinoxes, solstices or any date; latitude from the Sun's height.
Dot Product
Find the dot product of vectors from coordinates or from lengths and the angle, the cosine of the angle, the projection and a perpendicularity check.
Angle Between Vectors
Find the angle between two vectors from coordinates in 2D and 3D and the angle of a triangle from three points: exact cosine and the angle in degrees.
Factorial
Calculate the factorial n! and double factorial n!! exactly, with all digits, up to n = 1000. Number of digits, trailing zeros, Stirling formula.
Gas Laws
Ideal gas law pV = nRT and the combined gas law: pressure, volume, temperature and special processes.
Solutions
Mass percent of a solution: prepare, dilute, evaporate and mix solutions, the cross rule, with a step-by-step solution.
Empirical Formula
Find the empirical and molecular formula from mass percentages, molar mass or gas density, with a step-by-step solution.
Percent Greater Than
The calculator finds by what percent one number is greater than another.
Amount of Substance
Convert between mass, moles, gas volume at STP and number of particles: n = m/M, n = V/Vm, n = N/NA, with a solution.
Sector and Segment
Find the arc length, sector area, chord, height and area of a circular segment from the radius and angle, the arc length or the chord.
Pythagorean Theorem
Find the hypotenuse from the legs or a leg from the hypotenuse, the area and angles of a right triangle, and check whether a triangle is right.
Russian Transliteration
Convert Russian Cyrillic text to Latin letters by the passport rules, GOST 7.79-2000, ISO 9 or as a URL slug, and back.
Pyramid
Find the volume, slant height, lateral edge and surface area of a regular pyramid, a frustum and a regular tetrahedron.
Distance Between Points
Find the distance between two points from their coordinates in 2D and 3D with an exact answer and a step-by-step solution.
Atomic Structure
Protons, neutrons and electrons, electron configuration, shells and orbital diagram of any element or ion.
Newton's Second Law
Newton's second law F = m · a: find force, mass or acceleration with unit conversion and a step-by-step solution.
Chargaff's Rule
The percentage and number of nucleotides in DNA from one nucleotide, the DNA length and mass, and the number of hydrogen bonds.
Descriptive Statistics
Descriptive statistics of a data set: mean, median, mode, range, quartiles, variance and standard deviation, frequency table and chart.
Day of the Week
Find the day of the week for any date from year 1 to 9999. Solution by Zeller's congruence, day of the year, week number and month calendar.
DNA and RNA
From a DNA or mRNA fragment: the complementary strand, transcription, tRNA anticodons, amino acids from the genetic code table, DNA length and mass.
Stoichiometry
Solve stoichiometry problems: mass and volume of a product, limiting reactant, percent yield, with a step-by-step solution.
pH
pH of a strong acid or base solution, H+ and OH− concentrations, acidity and indicator colors, with a solution.
Subtract Percentage from a Number
The calculator subtracts a given percentage from any number with a step-by-step solution.
Speed, Distance, Time
Find speed, distance or time with v = s / t, unit conversion (km/h, m/s, minutes, hours) and a step-by-step solution.
Density
Density ρ = m / V, mass and volume with unit conversion (g/cm³, liters, grams), a solution and substance lookup by density.
Expected Value
Expected value, variance and standard deviation of a discrete random variable, Bernoulli formula and binomial distribution with a solution.
Cartesian and Polar
Convert points and equations between Cartesian and polar coordinates with a solution. Circles, lines and other curves.
Molarity
Molar concentration c = n/V: mass needed to prepare a solution, mass percent to molarity, dilution, with a solution.
Two's Complement
Sign-magnitude, ones' complement and two's complement of an integer in 8, 16 and 32 bits, and two's complement to decimal.
Text Size
The information size of a text I = K · i from characters, pages and lines or the alphabet size; how many characters fit in a file.
Percent Less Than
The calculator finds by what percent one number is less than another.
Periodic Table
Interactive periodic table: atomic mass, electron configuration, electronegativity and properties of every element.
Ellipse
Find the area, perimeter, focal distance and eccentricity of an ellipse from its semi-axes.
Matrix Operations
Matrix calculator: addition and subtraction, scalar and matrix multiplication, transpose and matrix powers with a step-by-step solution in fractions.
Matrix Rank
Find the rank of a matrix up to 6×6: reduction to row echelon form by Gaussian elimination with a detailed solution and pivot columns.
River Gradient
The fall of a river from the source and mouth elevations and the gradient in m/km (‰), with a solution.
Poetic Meter
Find the meter of a verse and the number of feet from marked stresses or a stress scheme: iamb, trochee, dactyl, amphibrach, anapest.
Efficiency and Levers
Efficiency η = W_out / W_in, useful work and work input, torque, the lever rule and inclined plane efficiency.
Hooke's Law
Hooke's law F = kx: spring force, spring constant, extension and elastic potential energy.
Oscillations and Waves
Period of a simple pendulum and a mass on a spring, pendulum length, frequency and wavelength.
Thin Lens
Thin lens equation 1/F = 1/d + 1/f: image distance, focal length, optical power, magnification and image properties.
Weight on Planets
How much you would weigh on the Moon, Mars, Jupiter and other planets: weight P = m · g and scale readings for all Solar System bodies.
Color Converter
Convert colors between HEX, RGB and HSL with a solution and the binary color code.
Humidity
Relative and absolute humidity, saturation deficit and dew point from the school table or the Magnus formula.
Truth Table
Build the truth table of a logical expression with intermediate columns, the order of operations, canonical DNF and CNF.
Compound Interest
The compound interest calculator works out the return on a deposit compounded monthly, quarterly or annually, with monthly contributions and a yearly table.
Moon Phase
The Moon phase and illumination on any date, the Moon's age and the exact times of new and full moons in your time zone.
Equation of a Line
Find the equation of a line through two points, from a point and a vector or the slope: general, slope-intercept, symmetric, parametric and intercept forms with a graph.
Image Size
The size of an uncompressed raster image I = w · h · i from dimensions and color depth or palette size; colors for a given size.
Resistors
Total resistance of resistors in series, parallel and combination circuits, with the current and voltage of each resistor.
Momentum
Momentum p = mv and its conservation: inelastic and elastic collisions, recoil and impulse.
What Percent of a Number
The calculator finds what percent one number is of another with a step-by-step solution.
Word Counter
Count characters with and without spaces, words, sentences and paragraphs, with frequent words and reading time.
Heat
Heat for heating and cooling, melting, boiling and burning fuel, and the heat balance of a mixture, with tables of substances.
Scientific Calculator
Scientific calculator with trigonometry, logarithms, powers, roots, factorials and brackets, showing the order of operations step by step.
Sine, Cosine, Tangent
The calculator finds the sine, cosine, tangent and cotangent of an angle in degrees or radians, converts degrees to radians, shows the quadrant, signs and reduction formulas. Exact values with roots.
Equation of a Plane
Find the equation of a plane through three points, from a point and a normal vector or two direction vectors: general and intercept forms, the normal vector.
Pressure
Pressure of solids and fluids: p = F/A, p = ρgh, force, area and depth with a step-by-step solution and unit conversion.
Coordinate Converter
Convert latitude and longitude between degrees, minutes, seconds and decimal degrees, with a solution.
Audio and Video Size
The size of an audio file I = f · i · k · t, audio duration from file size and the size of uncompressed video.
Ecological Pyramid
The mass and energy of each link of a food chain by the 10% rule and the share of energy passed to the next level.
Buoyant Force
Buoyant force F = ρgV, submerged volume, fluid density, and whether an object floats or sinks.
Electric Power and Cost
Work done by current W = VIt, power P = VI, energy in kWh and the cost of electricity at your rate.
Exponential, Log and Trig Equations
The calculator solves aˣ = b, logₐx = b, sin x = a, cos x = a and tan x = a with exact answers for standard values.
Time Calculator
Add and subtract hours, minutes and seconds, add a duration to a clock time and find the time between two clock times across midnight.
Decimal to Fraction
The calculator converts decimals to fractions and fractions to decimals, finds the repeating part of infinite decimals and shows the steps.
Biquadratic Equations
The calculator solves the biquadratic equation ax⁴ + bx² + c = 0 with the substitution t = x², step by step.
Cubic Equations
The calculator solves the cubic equation ax³ + bx² + cx + d = 0: rational root theorem, synthetic division, Cardano's formula.
Systems of Linear Equations
The calculator solves systems of 2 and 3 linear equations by Cramer's rule, Gaussian elimination and the inverse matrix method with exact fractions.
Linear Equations
The calculator solves the linear equation ax + b = cx + d step by step: moving terms, combining like terms and checking the answer.
Cone
Find the volume, slant height, lateral and total surface area of a cone and a frustum of a cone.
Sphere
Find the volume and surface area of a sphere from the radius, diameter, volume or area, and the volume of a spherical cap.
Julian and Gregorian
Convert dates between the Julian and Gregorian calendars: Old Style and New Style with a solution and the day of the week.
Astronomical Units
Convert kilometers, astronomical units, light-years and parsecs, with a solution and the light travel time.
Text and Binary
Convert text to binary, decimal and hexadecimal codes and back: ASCII, Unicode, UTF-8 and Windows-1251.
Year to Century
Finds the century from a year and the years of a century, and writes the century in Roman numerals. The year 1812 is in the 19th century.
Calories
Basal metabolic rate (BMR) and daily calorie needs from sex, age, height, weight and activity.
Business Days
Count business days between dates excluding weekends and optional holidays, working hours, and the date after N business days.
Population
Population density, natural increase, birth and death rates per mille, net migration and total increase.
Salinity
Water salinity in per mille, the mass of salts in seawater and the mass of water needed for a given amount of salt.
Mean Temperature
Daily, monthly and annual mean temperature and temperature range from readings, with a solution.
Coulomb's Law
Force between point charges F = k|q₁||q₂|/r², distance, charge and electric field strength.
Root Calculator
The calculator finds square roots, cube roots and roots of any index, simplifies radicals and shows a step-by-step solution.
Mixed Numbers
The calculator converts mixed numbers to improper fractions and improper fractions to mixed numbers with a step-by-step solution.
Percent to Fraction
The calculator converts percentages to fractions and decimals, and fractions and decimals to percentages, with a step-by-step solution.
Sum of Numbers 1 to N
The calculator finds the sum of all numbers from 1 to N or from M to N using the Gauss formula with a step-by-step solution.
Common Denominator
The calculator converts 2, 3 or 4 fractions to the least common denominator: it finds the LCM of the denominators, the extra factors and the new fractions.
Unix Timestamp
Converts a Unix timestamp to date and time (UTC and Moscow) and a date to a timestamp. Seconds and milliseconds.
Compare Numbers
The calculator compares whole numbers and decimals, positive and negative, and explains step by step which number is greater.
Divisors of a Number
The calculator finds all divisors of a number, how many there are and their sum, and checks whether the number is prime or composite.
Simplify Fractions
The calculator reduces a fraction to lowest terms: it finds the GCD with the Euclidean algorithm, divides the numerator and denominator by it and writes a mixed number.
Repeating Decimal to Fraction
The calculator converts a repeating decimal to a fraction using the rule of nines and shows a step-by-step solution.
VAT Calculator
The calculator adds VAT to a net amount or removes VAT from a gross amount at any rate, with a step-by-step calculation.
Quadratic Equations
The calculator solves ax² + bx + c = 0 using the discriminant: exact roots with simplified radicals, complex roots and a check with Vieta's formulas.
Division with Remainder
The calculator divides whole numbers with a remainder and finds the quotient and the remainder step by step, including negative numbers.
Exponent Calculator
The calculator raises whole and decimal numbers to any power, including negative exponents, with an exact result and a step-by-step solution.
Rounding Calculator
The calculator rounds numbers to the nearest thousand, hundred, ten, whole number, tenth, hundredth or thousandth with a step-by-step explanation.
Clock Angle
The calculator finds the angle between the hour and minute hands for any time, draws the clock face and shows a step-by-step solution.
Roman Numerals
The converter turns numbers from 1 to 3999 into Roman numerals and back, breaks them down by place value and checks that they are written correctly.
Proportion Calculator
The calculator solves a proportion a/b = c/d, finds the unknown term by cross-multiplication and shows the solution with a check.
Percent Change
The calculator shows by how many percent a value increased or decreased and what change is needed to get back to the original value.
Discount Calculator
The calculator finds the sale price, the discount percentage and the original price, and shows how much you save.
Day Length
Length of daylight, sunrise and sunset in local solar time for any latitude and date, polar day and polar night.
Gravitational Force
Gravitational force F = Gm₁m₂/r², distance, mass and the surface gravity of a planet.
Percent Error
Find absolute and relative (percent) error from an exact value or a series of measurements, with the solution.
Simple Interest
Simple interest: final amount and interest, annual rate or time using S = P(1 + rt/100), with the solution.
Ratio
Simplify a ratio a : b, find a missing term and split a quantity in a given ratio, with the solution.
Scientific Notation
Add, subtract, multiply and divide numbers written as a · 10ⁿ, with a normalised answer and a step-by-step solution.
P-Value
P-value from a z, t or chi-square statistic for one- and two-tailed tests, with a conclusion at the significance level.
Cylinder
Find the volume, base area, lateral and total surface area of a cylinder from the radius or diameter and height. Exact answer in terms of π.
Cuboid
Find the volume, surface area and diagonal of a rectangular cuboid from its dimensions, and the height from the volume or diagonal.
Prism
Find the volume, base area, lateral and total surface area of a regular n-gonal prism and a right prism.
Arithmetic Sequence
The calculator finds the n-th term, the common difference and the sum of the first n terms of an arithmetic sequence from any known data and checks whether a number is a term. Step-by-step solution.
Geometric Sequence
The calculator finds the n-th term, the common ratio, the sum of the first n terms of a geometric sequence and the sum of an infinite geometric series. Exact answer and step-by-step solution.
Logarithm Calculator
The calculator finds the logarithm to any base, the natural logarithm ln and the common logarithm log: the exact value when possible, otherwise an approximation. Step-by-step solution.
Scientific Notation
Convert a number to scientific notation and back: 0.00052 = 5.2 · 10⁻⁴. Step-by-step solution.
Function Grapher
Online function grapher: up to three functions on one plot, zeros, intersection points and a table of values. Polynomials, fractions, roots, absolute value, logarithms, sine and tangent.
Wavelength and Frequency
Wavelength and frequency converter: nanometers, meters, hertz and photon energy. Conversion with a solution and a table.
Angles
Angle converter: degrees, arcminutes, arcseconds, radians, gradians and turns. Conversion with a solution and a table.
Fuel Consumption
Fuel consumption converter: L/100 km, km/L and miles per gallon (US and UK). Conversion with a solution and a table.
Morse Code
Convert text to Morse code and back: Latin and Russian letters, digits and symbols with a code table.
Solution Concentrations
Concentration converter: mass fraction, molarity and g/L, taking solution density into account. Step-by-step solution.
Cooking Measures
How many grams are in a cup or a spoon: flour, sugar, salt, grains, oil and more. Conversion with a solution.
Electrical Units
Electrical units converter: current, voltage, resistance and capacitance. Convert mA, kV, kΩ and µF with a solution.
Percent and Per Mille
Parts converter: decimal and common fractions, percentages, per mille and ppm. Conversion with a solution and a table.
Frequency and Period
Frequency and period converter: Hz, kHz, MHz, rpm, rad/s and period in seconds. Conversion with a solution and a table.
Old Russian Units
Old Russian units converter: vershok, arshin, sazhen, versta, zolotnik, pud, vedro and desyatina. Conversion with a solution.
Cube
Find the volume, surface area, face diagonal and space diagonal of a cube from the edge, a diagonal, the volume or the area.
Clothing and Shoe Sizes
Convert clothing and shoe sizes between the Russian, European, US and UK systems. Size charts included.
Resistor Color Code
Find resistance from color bands and bands from a value, with a picture and tolerance.
Screen Size
Converts a screen diagonal between inches and centimeters and finds the width and height from the aspect ratio.
Probability
Probability of an event, addition and multiplication rules, conditional probability and "at least once", solved step by step.
Slope
Slope and angle of a line through two points, the equation y = mx + b and percent grade, with the solution.
Number Sequence
Find the pattern and next terms of a sequence, and Fibonacci numbers, with the solution.
Grade Needed
Find the grade or the number of top marks needed to reach a target average, with the solution.
Z-Score
Z-score of a value, percentile and normal probabilities, value from z and calculation from a sample.
Voltage Drop
Voltage drop and power loss in copper and aluminium wire from length, cross-section and current.
Horsepower
Convert hp and kW, find power from torque and RPM, and estimate engine power from a quarter-mile run.
Age on Other Planets
How old you are on Mercury, Venus, Mars, Jupiter and other planets and when your next birthday on each of them will be.
Pressure
Pressure converter: pascals, kPa, MPa, bars, atmospheres, mmHg. Exact conversion with a solution and a table.
Energy
Energy converter: J, kJ, calories, kilocalories, kWh and electronvolts. Conversion with a solution and a table.
Force
Force converter: N, kN, MN, dynes, kgf and pound-force. Exact conversion with a solution and a table.
Power
Power converter: W, kW, MW and horsepower. Conversion with a solution and a table.
Density
Density converter: kg/m³, g/cm³, g/L, g/mL and t/m³. Exact conversion with a solution and a table.
Acceleration
Acceleration converter: m/s², cm/s², km/h per second and g. Exact conversion with a solution and a table.
SI Prefixes
SI prefix converter from yocto to yotta. Convert between nano-, micro-, milli-, kilo- and mega- with a solution and a table.
Radiation Units
Radiation units converter: becquerels, curies, grays, rads, sieverts, rems and roentgens. Conversion with a solution.
Data Rate
Data rate converter: bit/s, Kbit/s, Mbit/s, Gbit/s and MB/s. Conversion with a solution and a table.
Data Units
Data units converter: bits, bytes, KB, MB, GB, TB, KiB and MiB. Conversion with a solution and a table.
Percentage of a Number
The calculator finds a given percentage of a number with a step-by-step solution.
Basic Calculator
Free online math calculator. Adds, subtracts, multiplies and divides numbers, works with brackets and decimals.
Text Case
Changes text case: UPPER CASE, lower case, Sentence case, Title Case and inverted case.
Function Analysis
Complete step-by-step function analysis: domain, symmetry, zeros, asymptotes, derivative, extrema, concavity, inflection points and the graph. Polynomials and rational functions.
Loan Calculator
Monthly payment, total interest and repayment schedule for amortized and declining-balance loans.
Tire Size
Tire diameter, circumference and revolutions, comparison of two sizes and speedometer error.
Days Calculator
This free date calculator calculates the difference between two dates. It can also add or subtract from a date. Both calculators work with business days and calendar days.
Budget
Split income by the 50/30/20 rule and find what is left after a list of expenses.
BMI
Adult body mass index from height and weight: WHO category and healthy weight range.
Concrete
Concrete volume for a slab, column or strip foundation, with weight and approximate cement use.
Fuel Cost
How much fuel a trip needs and what it costs, and actual consumption from mileage.
Age
Exact age from a date of birth: full years, months and days, total days and weeks, and time until the next birthday.
Sample Size
Sample size from confidence level, margin of error and population size, plus the margin of error for a known sample.
ROI and Payback
Return on investment, annualized return and payback period, with the solution.
Margin and Markup
Margin and markup from cost and price, and the selling price for a target margin or markup.
PV, FV and IRR
Future and present value, savings with regular deposits, NPV and internal rate of return.
Depreciation
Depreciation by the straight-line, declining-balance and sum-of-years methods, with a yearly table.
Tip Calculator
Tip amount, total and each person's share when splitting a bill.
Currency Conversion
Convert an amount at a rate you enter, with a fee, and calculate a cross rate.
Inflation
Future price, purchasing power, average inflation from prices and cumulative inflation over several years.
GDP
GDP by the expenditure approach, GDP per capita, growth rate and real GDP via the deflator.
Macros
How many grams of protein, fat and carbohydrate suit your daily calories at different ratios.
Running Pace
Running pace, time or distance, and predicted results for other distances.
Heart Rate Zones
Maximum heart rate by age and training zones by the simple and Karvonen methods.
Tile
How many tiles and boxes for a floor or wall, including joints and a cutting allowance.
Roof
Gable roof area, rafter length and ridge height from building size, slope and overhangs.
Stairs
Number of steps, rise, run, length and angle of stairs by the comfortable step formula.
Room Area
Floor and wall area minus windows and doors, the total for several rooms and material cost.
Work Hours
Hours worked for a day or week minus breaks, including night shifts, and pay at an hourly rate.
Confidence Interval
Confidence interval for a mean or a proportion at the 90, 95 or 99% level, from summary data or a sample, with the solution.
Partial Fractions
The decomposition of a rational function into partial fractions with exact coefficients.
Countdown
How many days, hours, minutes and seconds are left until a date: a live countdown to New Year, a birthday or any event.
Riemann Zeta Function
The value of the Riemann zeta function for real s.
Numerical Methods
Solve an equation by bisection, Newton’s method or false position with a table of steps.
Partial Derivatives and Gradient
First and second partial derivatives of a function of several variables and the gradient at a point.
Normal Line and Corners
The normal line to a graph at a point and the corner points of a function on an interval.
Area and Revolution
The area between curves and in polar coordinates, the volume and surface of a solid of revolution.
Interpolation
Linear interpolation and a polynomial through given points with exact values.
3D Plots
A static picture of the surface z = f(x, y) on a given range.
Venn Diagram
A diagram for two and three sets and the size of the union by the inclusion–exclusion formula.
EGE and OGE Scores
Convert Russian EGE primary scores to test scores and OGE scores to marks by the official 2026 scales.
Differential Equations
Solve the main types of differential equations and initial value problems numerically.
Sleep
Bedtime or wake-up time based on 90-minute sleep cycles.
Place Value
How many digits and periods a number has, the digit in each place and the total ones, tens, hundreds and thousands.
Fibonacci Numbers
The sequence from F₀ to Fₙ, the exact value of Fₙ and the sum of the first terms, with the solution.
Polynomial Equations
Quartic equations and polynomials up to degree 10: real and complex roots with multiplicity.
System Consistency
The consistency of a system of linear equations by ranks and its general solution, by the Rouché–Capelli theorem.
Correlation and Regression
The Pearson coefficient, the linear regression equation and a plot of the points and the line.
Russian Utility Subsidy
An estimate of the Russian housing and utility subsidy from income and costs.
Russian Length of Service
Work periods added up into years, months and days, handling overlaps.
Heat Index
Feels-like temperature in hot weather from air temperature and relative humidity, with a danger level.
Wind Chill
How cold it feels in the wind: wind chill from air temperature and wind speed, with frostbite risk.
Random Numbers and Dice
Random numbers in a range, with or without repeats, and rolling dice.
Base64
Encode text to Base64 and back, with full Unicode support. Text is not sent to the server.
URL Encode
Encode and decode URLs and query parameters. Text is not sent to the server.
Password Generator
Strong random passwords generated in your browser, with length, character sets and a strength estimate. Never sent to the server.
Ideal Weight
Estimated weight from height and sex: Devine, Robinson, Miller and Hamwi formulas and the healthy BMI range.
Pregnancy
Gestational age, trimester and estimated due date from the last period or conception date.
Ovulation
Estimated ovulation date, fertile window and upcoming periods for the next three cycles.
Rational or Irrational
Check whether a number, root, fraction or constant is rational, with the prime factorization and an explanation.
Consecutive Number Sums
Whether a number can be written as a sum of consecutive natural numbers, and all such sums, with the solution.
Fraction to a Power
Raise a common fraction to a whole power, including negative powers, with an exact result and steps.
Sum of a Sequence
The sum of the first n terms of common sequences by closed formulas, with an exact result and steps.
General Term Formula
A formula for the n-th term from the first terms of a sequence, with a check and the next terms.
Radical Equations
Solve equations with roots: the conditions, raising to a power and a check of each root, step by step.
Solve for a Variable
Isolate the chosen variable in a linear equation, expanding brackets and moving terms step by step.
Systems of Inequalities
Solve systems of linear, quadratic and rational inequalities in one variable with a number line.
Inequalities on a Plane
The solution of a system of linear inequalities in x and y on the plane, with the vertices of the region.
Maximum and Minimum
The maximum and minimum of a function on a closed interval: the derivative, critical points and a graph.
Period and Range
The smallest period of a function and an estimate of its range, with a graph and the solution.
Any Quadrilateral
The area of any quadrilateral from the diagonals and angle, or from the sides with a diagonal or angles.
Annular Sector
The area of an annular sector, arc lengths and perimeter from two radii and an angle, with a figure.
Octahedron
The edge, volume, surface area and sphere radii of a regular octahedron from one value.
Golden Ratio
The whole segment and the larger and smaller parts in the golden proportion from one known value.
Circle Equation
The equation of a circle from its centre and radius or a point, and the centre and radius from the general form.
Angle Between Lines
The angle between two lines from their general equations, their relative position and intersection, with a figure.
Two Planes
The angle between two planes, their relative position and the distance between parallel planes.
Triangle from Coordinates
Area, medians, orthocenter, incenter, circumcenter and the position of a point from the vertex coordinates.
Vector Basis
Check whether vectors form a basis and decompose a vector in the basis, with the solution.
Eigenvalues and Eigenvectors
Eigenvalues and eigenvectors of a matrix through the characteristic polynomial, step by step.
Minor and Cofactor
The minor and cofactor of a chosen element of a square matrix, with the solution.
Permutation Operations
The inverse permutation, inversions and parity, the cycle decomposition and the order of a permutation.
Binomial and Pascal’s Triangle
The expansion of a binomial and rows of Pascal’s triangle with exact coefficients.
Combinatorial Equations
Equations with combinations, arrangements and permutations where the unknown is a natural number n.
Set Operations
The union, intersection, difference and symmetric difference of sets, and a subset check.
Subsets and Power Set
All subsets of a set and their number, with the solution.
GPA Calculator
Grade point average from marks or letter grades, weighted by hours or credits.
Quality of Knowledge
Pass rate, quality of knowledge, degree of learning and the class average from the number of marks.
Water Density
The density of fresh and salt water from temperature and salinity.
Speed of Sound
The speed of sound in dry air from the temperature, with the solution.
Coefficient of Friction
The coefficient of friction, friction force and normal force, and the coefficient from a slope angle.
Ball Flight
The range, height and flight time of a ball with air drag, with a plot of the path.
Arrhenius Equation
The reaction rate constant, the activation energy from two experiments and the constant at another temperature.
Telescope
Magnification, exit pupil, field of view, resolution, limiting magnitude and the Newtonian diagonal.
Sky Position and Visibility
The altitude and azimuth of an object, culminations and visibility over the year from its coordinates and your location.
Angular Distance
The angular distance between two points on the celestial sphere from their coordinates.
Celestial Coordinates
Convert between equatorial, ecliptic and galactic coordinates for epoch J2000.
Astrophotometry
Magnitude, brightness ratio, absolute magnitude and distance.
Atmospheric Refraction
Refraction and the conversion of true altitude to apparent and back, with pressure and temperature.
Sidereal Time
Local sidereal time from the date, universal time and longitude.
Magnetic Units
Flux density, field strength, magnetomotive force, magnetic flux and inductance.
Light Units
Luminous intensity, illuminance, exitance, luminous flux and luminous energy.
Flow Rate
Units of volumetric and mass flow of liquids and gases.
Viscosity
Units of kinematic and dynamic viscosity: stokes, centistokes, poise.
Torque
Units of torque in the metric and imperial systems.
Wind Force
Convert wind speed to the Beaufort scale and back.
Taylor, Maclaurin, Fourier Series
Expand a function in a Taylor, Maclaurin or Fourier series with a graph of the approximation.
Laplace Transform
The image of a function and the original from an image, using a table and partial fractions.
Multiple Integrals
The value of a double or triple integral by numerical calculation with an accuracy check.
Simplify Expressions
Expand brackets, combine like terms and cancel fractions in expressions with letters.
Series Convergence and Sum
An estimate of the convergence of a numerical series by tests and its approximate sum.
Nonlinear Equations
Solve any equation on an interval and a system of two nonlinear equations.
Debt Payoff
The time to repay with a given payment and a payoff plan for several debts and credit cards.
Debt Consolidation
Compare current debts with one new loan: payment, term and total gain.
Loan Rate and APR
The rate from a payment and an estimate of the full cost of a loan with fees.
Cash Back or Low Rate
Compare buying on credit with cash back or with a low rate.
Loan Balance
The remaining debt on a loan after a given number of payments.
Lease
The payment, total and cost increase of a lease with a down payment and residual value.
Investment Parameters
The final or starting amount, monthly deposit, term or return of an investment.
Annuities
Savings from deposits, payout size and the present value of a perpetuity.
Bonds
The price, yield to maturity and duration of a bond.
Mutual Fund
The growth of a fund investment after a management fee and a purchase load.
Cost of Education
The future cost of education and the amount to save per month.
Break-Even Point
The sales volume and revenue with neither profit nor loss.
Operating and Financial Leverage
The operating, financial and total leverage of a business.
Inventory Turnover
The inventory turnover ratio and the days per turn.
Economic Order Quantity
The optimal order size, the number of orders and the costs by Wilson’s formula.
Venue Profitability
The revenue, costs, profit and payback of a café or a small venue.
Salary Conversion
Convert pay between an hour, day, week, month and year.
Is Work Worth It
Compare income and costs with and without going to work.
Recurring Charges
Payment dates at a given interval and the running total.
Retirement Savings
What you save by retirement, the contribution needed, and a lump sum versus monthly payouts.
Mortgage
The mortgage payment with tax and insurance, early payments and the Russian tax deduction.
Housing Affordability
What home and rent your income allows, and the down payment and time to save it.
Rent vs Buy
A mortgage or renting and investing the difference, with wealth compared year by year.
Refinance
Whether a new loan pays off: the payment, the total paid and the payback of the costs.
Property Yield
The rental yield, payback, return including a sale and cash flow with a loan.
Loan Chances
A rough score from debt load, credit history and job tenure. Banks have their own methods.
Family Budget and Estimate
Family spending by item, what is left, and an estimate for a wedding or other event.
Body Composition
Body fat, lean mass, body shape and body surface area by formulas.
Pregnancy Weight Gain
The recommended weight gain range by week of pregnancy based on BMI.
Calories Burned
Calories used in running, walking, swimming and other activities.
One Rep Max
The one rep max estimated from the weight and reps, with a table of training weights.
GFR
The eGFR from creatinine by CKD-EPI 2021 and Schwartz. A doctor evaluates the result.
Blood Alcohol
A rough blood alcohol estimate. The result does not show whether you may drive.
Child Height Forecast
A child’s adult height from the parents’ heights with a range. The result is an estimate.
Air Conditioner Size
The air conditioner power from the room area and conditions, in kW and BTU.
Mulch and Gravel
The volume, mass and bags of mulch, gravel, sand and stone by area and depth.
Horsepower from Acceleration
Engine power estimated from the mass and acceleration or a quarter mile result.
Bra Size
A bra size from measurements and a conversion between RU, EU, US, UK, FR and IT.
Russian Income Tax
Russian income tax for 2026, dividends, employer contributions and the total tax load.
Russian Simplified Tax
The Russian simplified tax at 6% and 15% and sole trader contributions for 2026.
Russian Home Sale Tax
The tax on a home sale in Russia and the income tax refund on a purchase.
Russian Tax Fine and Penalty
The fine for a late return, penalty interest on tax and a contract penalty in Russia.
Russian Court Fee
The Russian court fee by claim amount for general and arbitration courts.
Russian INN and OGRN Check
Verifies the check digits of Russian INN, OGRN and OGRNIP numbers in your browser.
Russian Vacation Pay
Russian vacation pay from average earnings over 12 months, with partial months.
Russian Late Pay Compensation
Compensation for late pay under Article 236 of the Russian Labor Code.
Russian Insurance Pension
An estimate of the Russian insurance pension from points or salary and years of work.