Math Calculators
Math calculators covering percentages, fractions, algebra, geometry and statistics.
87 calculators
Absolute Value Calculator — Find |x|, Distance & Solve |x|=a
Free absolute value calculator: instantly computes |x|, number-line distance, solutions to |x|=a, and complex modulus.
Add Time Calculator — Sum Hours, Minutes & Seconds
Free add time calculator: sum two durations in weeks, days, hours, minutes and seconds and instantly see the total normalized.
Arc Length Calculator — Radius, Degrees/Radians, Chord
Free arc length calculator: enter the radius and central angle (degrees or radians) to get arc length, radians, chord length and sector area instantly.
Area Calculator — Rectangle, Triangle & Circle
Free area calculator for rectangles, triangles and circles. Enter length, width or radius in feet and get square feet, square yards and acres instantly.
Area Converter Calculator — Sq M, Sq Ft, Acres
Free area unit converter: convert square meters to square feet, acres, square miles, square yards and hectares instantly.
Average Calculator — Mean, Median & Range
Free average calculator: enter five numbers to instantly find the arithmetic mean, median, and range. Supports negatives and decimals.
Binary Calculator: Decimal to Binary, Hex & Octal
Free binary calculator converts whole numbers between decimal (base 10), binary (base 2), hex (base 16) and octal (base 8), with padded bits.
Binomial Probability Calculator — P(X=k) and CDF
Binomial probability calculator: exact P(X=k), cumulative P(X<=k), expected value and variance for n Bernoulli trials with success probability p.
Circle Area Calculator — Area, Circumference & Diameter
Free circle area calculator: enter the radius (cm, m, in, ft) to instantly get the area, circumference and diameter in centimeters.
Circle Circumference Calculator — Find C, Diameter, Area
Free circle circumference calculator: enter the radius (cm, m, in, ft) to instantly get C, diameter and area in centimeters.
Combinations Calculator — n Choose k (No Order)
Free combinations calculator: how many ways to choose k items from n items when order does not matter. See the n-choose-k formula, examples, and odds.
Cone Volume Calculator (Radius & Height)
Free cone volume calculator using V = 1/3*pi*r^2*h. Works in cm, m, in, ft; also finds slant height, base area, lateral and total surface area.
Confidence Interval Calculator (Mean)
Free confidence interval calculator: enter the mean, standard deviation, and n to get the margin of error and 90%, 95%, or 99% bounds.
Correlation Calculator — Compute Pearson r & Strength
Free correlation calculator: compute the Pearson correlation coefficient r, r-squared, and a 95% confidence interval from two paired data sets instantly.
Correlation Coefficient Calculator — Pearson r & p-value
Free correlation coefficient calculator: compute the Pearson r, r-squared and p-value from two paired data sets. Fast, accurate, no sign-up.
Covariance Calculator — Sample & Population
Free covariance calculator: compute sample and population covariance between two data sets, plus means, correlation coefficient, and step-by-step results.
Cube Volume Calculator (Side to Volume)
Free cube volume calculator: V = side^3. Also finds surface area, face area, space diagonal and filled volume from the edge length.
Cylinder Volume Calculator (Radius & Height)
Free cylinder volume calculator using V = pi*r^2*h. Works in cm, m, in, ft; also finds base area, lateral and total surface area.
Data Storage Converter — Bytes, KB, MB, GB & TB Calculator
Free data storage unit converter: convert bytes to KB, MB, GB, TB and back instantly. Binary 1024-based conversion for drives, files and memory.
Date Calculator — Days Between & Add Days
Free date calculator: count the days between two dates, add or subtract days, and instantly see the result date, weekday, and elapsed years/months/days.
Day of Week Calculator for Any Calendar Date
Find the weekday of any past or future date instantly. Enter year, month and day to see Monday-through-Sunday, weekend status and day-of-year.
Days Until Christmas Calculator — Countdown to Dec 25
Free Christmas countdown calculator: see exactly how many days, weeks and hours until December 25, with automatic rollover to next Christmas.
Decimal to Fraction Calculator
Convert any decimal to a simplified fraction instantly. Supports repeating decimals, negatives, mixed numbers, and shows the percent equivalent.
Rectangle Diagonal Calculator — Diagonal, Area & Perimeter
Free rectangle diagonal calculator: enter length and width to instantly get the diagonal (Pythagorean theorem), area, perimeter and corner angle.
Distance Calculator — Distance Between Two Points
Free distance calculator finds the straight-line (Euclidean) and grid (Manhattan) distance between two points (x1,y1) and (x2,y2), plus their midpoint.
Distance Formula Calculator — Between Two Points
Free distance formula calculator finds the straight-line distance between two points (x1,y1) and (x2,y2), plus midpoint and slope, step by step.
Doubling Time Calculator: Years to Double at Any Growth Rate
Free doubling time calculator: exact years and months to double at any annual growth rate, annual/monthly/continuous compounding, plus Rule of 72.
Equation Solver — Linear & Quadratic Calculator
Solve linear and quadratic equations step by step. Enter coefficients a, b, c to get roots, discriminant, and the exact solution for ax² + bx + c = 0.
Exponent Calculator — Raise a Number to the Nth Power
Free exponent calculator: compute base^n instantly, with expanded multiplication, scientific notation and digit count. Try 2^10, 5^3 or 10^6.
Factorial Calculator — Compute n!
Free factorial calculator: compute n! for non-negative integers, plus digit count, trailing zeros, and n!/(m!k!) ratios.
Fraction Addition Calculator — Add & Simplify Fractions
Free fraction addition calculator: add two fractions, find the LCD, reduce to lowest terms, and see the mixed number and decimal result.
Fraction Calculator — Add, Subtract, Multiply & Divide
Free online fraction calculator: add, subtract, multiply, divide and simplify fractions step by step. See reduced fraction, mixed number and decimal.
Fraction Division Calculator — Divide & Simplify Fractions
Free fraction division calculator: divide two fractions, keep-change-flip by the reciprocal, reduce to lowest terms, and see the decimal result.
Fraction Multiplication Calculator — Multiply & Simplify
Free fraction multiplication calculator: multiply two fractions, cross-cancel common factors, reduce to lowest terms, and see the decimal result.
Fraction Subtraction Calculator — Subtract & Simplify
Free fraction subtraction calculator: subtract two fractions, find the LCD, reduce to lowest terms, and see the mixed number and decimal result.
Fraction to Percent Calculator — Convert Any Fraction to %
Free fraction to percent calculator. Enter numerator and denominator to instantly convert a fraction to a percentage, with decimal and simplified form.
Future Value Calculator — Lump Sum Growth Over Time
Free future value calculator: grow a single lump sum with the TVM formula FV = PV × (1+r)^n. See interest earned, total growth and your future nest egg.
GCD Calculator — Greatest Common Divisor & LCM
Free GCD calculator: instantly find the greatest common divisor of two integers with the Euclidean algorithm, plus LCM and the reduced ratio.
GCF Calculator — Greatest Common Factor of Two Numbers
Free GCF calculator: instantly find the greatest common factor of two integers, reduce a fraction, and derive the LCM.
Julian Date Calculator — Calendar Date to JD
Convert any Gregorian calendar date and UTC time to the astronomical Julian Date (JD), plus Modified Julian Date (MJD) and days since the J2000 epoch.
LCM Calculator — Find the Least Common Multiple
Free least common multiple calculator: instantly finds the LCM of two integers, and shows the GCD, absolute product, and multiple counts.
Length Converter Calculator — Inches, Feet, Meters & Miles
Free length unit converter: convert inches to cm, feet to meters, miles to km, yards to feet and millimeters instantly with exact SI definitions.
Logarithm Calculator — Base-b, Natural, log10 & log2
Free logarithm calculator: compute log with any custom base, plus natural log (ln), log base 10, log base 2, and antilog. Instant step-by-step results.
Matrix Calculator — Determinant, Inverse & Multiplication
Free 2x2 matrix calculator: compute determinant, inverse, transpose, and A times B multiplication. Linear algebra tool for students and engineers.
Meeting Time Zone Calculator — ET, PT, London & Tokyo
Free meeting time zone converter: instantly turn one local meeting time into ET, PT, London and Tokyo equivalents with day-shift flags.
Midpoint Calculator — Center Between Two Points
Free midpoint calculator finds the center point between two points (x1,y1) and (x2,y2), plus segment length, half-distance to the midpoint, and slope.
Mixed Number Calculator — Improper to Mixed
Free mixed number calculator: convert an improper fraction (numerator/denominator) to a reduced mixed number, whole number, or decimal, with sign handling.
Normal Distribution Calculator (CDF, PDF & Percentile)
Free normal distribution calculator: CDF area below/above x, probability density, percentile rank, and area between two bounds for any mean and sigma.
Percentage Calculator — Find P% of X & Percent Change
Free percentage calculator for the three common questions: what is P% of X, Y is what percent of X, and the percent change from X to Y.
Perimeter Calculator — Rectangle, Square, Triangle & Circle
Perimeter calculator for rectangles, squares, triangles and circles. Enter sides or radius to get the outer boundary length plus enclosed area.
Permutations Calculator — n P k (Order Matters)
Free permutations calculator: how many ordered ways to arrange k items from n items. See the nPk formula, examples, and the difference vs combinations.
Portfolio Variance Calculator — 2-Asset Risk & Std Dev
2-asset portfolio variance calculator: enter weights, variances and covariance to get portfolio variance, std dev and diversification benefit.
Present Value Calculator — PV of Future Money
Free present value calculator that discounts a future sum back to today at your chosen rate. Instantly shows PV, discount factor, and total discount.
Probability Calculator — P(A), P(not A), P(A and B)
Free probability calculator finds P(A), P(not A), P(A and B) for independent events and P(A or B) for mutually exclusive events. Enter trials and successes
Pythagorean Theorem Calculator — Find c, Angles & Area
Free Pythagorean theorem calculator: enter legs a and b to instantly solve hypotenuse c, both acute angles, area and perimeter of a right triangle.
Pythagorean Theorem Calculator — Solve Missing Side
Free Pythagorean theorem calculator: enter any two sides to instantly solve the missing leg or hypotenuse of a right triangle with a² + b² = c².
Quadratic Calculator — Solve Ax²+Bx+C=0
Free quadratic calculator solves ax² + bx + c = 0: discriminant, real and complex roots, vertex, parabola direction and factored form.
Quadratic Equation Calculator (Ax² + Bx + C = 0)
Solve any quadratic equation step by step: discriminant, real and complex roots, Vieta's sum and product of roots, and the factored form.
Range Calculator — Find Min, Max & Spread
Free range calculator: enter a list of numbers to instantly find the minimum, maximum, and range (spread). Supports negatives, decimals, and large values.
Ratio Calculator — Simplify, Scale & Split Ratios
Free ratio calculator to simplify a:b:c to lowest terms, scale a ratio to find a missing value, and split a total amount by a ratio.
Rectangle Area Calculator — Area, Perimeter & Diagonal
Free rectangle area calculator: enter length and width to instantly get area, perimeter and diagonal in feet, inches, cm or meters.
Regression Line Calculator — OLS Slope, Intercept & R²
Free regression line calculator: fit an OLS line y = mx + b from paired data. Get slope, intercept, R² and slope confidence interval instantly.
Roman Numeral Converter — Decode Roman Numerals to Numbers
Roman numeral converter: enter the M, hundreds, tens and ones groups to decode the Arabic value and see what each Roman group is worth.
Scientific Calculator — Trig, Logs & Roots
Free online scientific calculator: instantly computes sin, cos, tan, square root, powers, logarithms, factorial, e^x and pi values in radians or degrees.
Simplify Expression Calculator — Combine Like Terms & Expand
Free simplify expression calculator for linear and quadratic shortcuts: combine like terms and expand (x+p)(x+q) binomials with exact coefficients.
Simplify Fractions Calculator — Reduce to Lowest Terms
Free simplify fractions calculator: reduce any fraction to its simplest form with the GCD, and instantly see the mixed number and decimal equivalent.
Slope Calculator — Find Slope, Angle & Intercept
Free slope calculator finds the slope of a line from two points, plus angle of incline, y-intercept, x-intercept, distance, midpoint and the line equation.
Slope Intercept Form Calculator — y = mx + b
Free slope intercept form calculator converts two points or standard form Ax+By=C into y=mx+b, with slope m, y-intercept b, x-intercept and line equation.
Speed Converter Calculator — mph, km/h, m/s & Knots
Free speed unit converter: convert mph to km/h, km/h to mph, m/s, ft/s and knots instantly. NIST-exact factors for driving, aviation and running.
Square Root Calculator — Find √x Instantly
Free square root calculator: instantly finds √x, the square, and any nth root, perfect for perfect squares, decimals, and large numbers.
Standard Deviation Calculator — Population & Sample
Free standard deviation calculator: compute population and sample SD, variance, and mean from up to 8 data points instantly.
Temperature Converter — Celsius, Fahrenheit & Kelvin
Free temperature converter: convert Celsius to Fahrenheit, Fahrenheit to Celsius, and Kelvin instantly with exact NIST definitions.
Time Converter — Seconds, Minutes, Hours & Days
Free time converter: convert seconds, minutes, hours, days, weeks and milliseconds instantly with exact 60/24/7 unit constants.
Time Duration Calculator — Elapsed Hours & Minutes
Free time duration calculator: elapsed hours and minutes between a start and end clock time, with automatic overnight crossing. Total in h, min and sec.
Time Zone Converter — NY, London, Dubai, Tokyo, Sydney
Free time zone converter: turn one local time into New York, London, Dubai, Tokyo and Sydney equivalents with next-day flags.
Trapezoid Area Calculator — Bases & Height
Free trapezoid area calculator: enter the two parallel bases and the height to instantly get the area in square feet, inches, cm or meters.
Triangle Area Calculator — Base, Height or 3-Side Heron's
Free triangle area calculator: enter base and height, or all three sides (Heron's formula), to instantly get the area in square feet, inches, cm or meters.
Triangle Calculator — Sides, Angles, Perimeter & Area
Free triangle calculator: enter all three sides to instantly get perimeter, Heron's area, and all three interior angles in degrees for any triangle.
Unit Converter — Length, Weight, Volume & Temperature
Free online unit converter: instantly convert length, weight, volume and temperature between metric and imperial units with exact NIST factors.
Variance Calculator — Population & Sample (σ² and s²)
Free variance calculator: compute population and sample variance, mean, and standard deviation from any comma-separated data set.
Volume Calculator — Cube, Cylinder, Sphere & Prism
Volume calculator for cubes, cylinders, spheres and prisms. Enter dimensions in feet and get cubic feet, yards and gallons instantly.
Volume Converter Calculator — Gallons, Liters, Cups, Ounces
Free volume unit converter: convert gallons to liters, liters to gallons, cups to mL, fluid ounces to liters and cubic feet instantly.
Week Number Calculator — ISO Week of the Year
Find the ISO week number of any calendar date instantly. See week-of-year, ISO year, weekday and week count for payroll, sprints and project tracking.
Weeks Between Dates Calculator — Count Any Span
Free weeks between dates calculator: count exact weeks, whole weeks plus leftover days, and months between two calendar dates, with leap-year handling.
Weight Converter — kg to lb, oz, Stone & Tons
Free weight converter: convert kg to lb, pounds to kg, ounces to grams, stone to pounds, and US short tons to kilograms with exact avoirdupois factors.
What Percentage Calculator — Part Out of Whole
Free what percentage calculator: find what percent one number is of another (A is what % of B), with the ratio, decimal and missing-percent complement shown.
Z-Score Calculator (with Percentile & P-Value)
Free z-score calculator: convert a raw score to a standardized z-score, percentile rank, and two-tailed p-value from the mean and standard deviation.