Education & Math
Math and statistics calculators with step-by-step formulas and worked examples for students and professionals.
Percentage Calculator
Calculate percentages three ways: find a percent of a number, find what percent one number is of another, or calculate percent change between two values.
Percentage Increase Calculator
Calculate percentage increase between two values with the standard formula, a worked step-by-step example, and the absolute difference shown alongside.
Percentage Decrease Calculator
Calculate percentage decrease between two values with the standard formula, a worked example, and the absolute difference shown alongside the result.
Fraction Calculator
Add, subtract, multiply and divide fractions with automatically simplified results, the decimal equivalent, and step-by-step formulas for each operation.
Decimal to Fraction Calculator
Convert any terminating decimal to a simplified fraction with the place-value method, plus the equivalent percentage. Example: 0.625 = 5/8 = 62.5%.
Ratio Calculator
Simplify a ratio to lowest terms, express it in 1:n form, and scale it to a new first term. Example: 4:6 simplifies to 2:3 and scales to 10:15.
Average Calculator
Calculate the average (arithmetic mean) of a list of numbers, with the sum, count, minimum and maximum shown alongside. Includes a worked example.
Scientific Calculator
Free online scientific calculator: trig in radians or degrees, roots, logs, exponents, constants pi and e — evaluated with a safe whitelist expression parser.
Mean Calculator
Calculate the arithmetic, geometric and harmonic means of a data set, with formulas, a worked example, and guidance on when each mean is appropriate.
Median Calculator
Find the median, mode and range of a data set with worked examples. Handles even-sized lists and multiple modes, and explains median vs mean for skewed data.
Standard Deviation Calculator
Calculate sample and population standard deviation, variance and mean for any data set, with the n-1 vs n distinction explained and a worked example.
Probability Calculator
Calculate the probability of two independent events: both occurring, either occurring, neither occurring, and the complement — with formulas and examples.
Sample Size Calculator
Calculate the survey sample size you need using Cochran's formula with finite population correction, at 90%, 95% or 99% confidence and your margin of error.
Confidence Interval Calculator
Calculate a z-based confidence interval for a mean from the sample mean, standard deviation and size, with the margin of error and standard error shown.
Z-Score Calculator
Calculate a z-score from a value, mean and standard deviation, plus the normal-distribution percentile and the share of values above. Worked example inside.
Normal Distribution Calculator
Calculate normal-distribution probabilities — P(X < x), P(X > x) or P(x < X < b) — from a mean and standard deviation, with the z-score shown.
Binomial Distribution Calculator
Calculate binomial probabilities — exactly k, at most k, or at least k successes — from the number of trials and success probability, with mean and SD.
T-Test Calculator
Run a one-sample or two-sample (Welch's) t-test from summary statistics. Get the t-statistic, degrees of freedom and two-tailed p-value instantly.
Chi-Square Test Calculator
Run a chi-square goodness-of-fit test from observed and expected counts. Get the χ² statistic, degrees of freedom and p-value instantly.
Correlation Calculator
Calculate the Pearson correlation coefficient (r), R², and the least-squares regression line from paired x and y data. Free and instant.
Bayes' Theorem Calculator
Calculate a posterior probability with Bayes' theorem from a prior, sensitivity and false-positive rate. Classic base-rate example included.
Random Number Generator
Generate random integers in any range, with or without repeats. Seeded so the same seed always reproduces the same draw — useful for teaching and research.
Quadratic Equation Calculator
Solve ax^2 + bx + c = 0 with the quadratic formula. Shows real or complex roots and the discriminant, with a worked step-by-step example.
Log Calculator
Calculate logarithms in any base with the change-of-base formula, plus the natural log (ln), common log (log10) and binary log (log2) shown together.
Exponent Calculator
Raise any base to any power, including negative and fractional exponents, with the result in plain and scientific notation and the exponent rules explained.
Prime Number Calculator
Check whether a number is prime, get its full prime factorization, and find the next prime — with trial division explained and worked examples.
Matrix Calculator
Calculate the determinant, trace and (for 2x2) inverse of a 2x2 or 3x3 matrix from row-major entries, with cofactor expansion shown step by step.
System of Equations Calculator
Solve a system of 2 or 3 linear equations by Gaussian elimination. Enter the augmented matrix coefficients and get x, y (and z) instantly.
Complex Number Calculator
Add, subtract, multiply or divide two complex numbers (a + bi) and see the result, modulus and argument instantly. Free complex arithmetic calculator.
Exponential Growth Calculator
Calculate exponential growth or decay over time using the compound growth formula. Get the final value, total change and doubling or halving time.
Arithmetic Sequence Calculator
Find the nth term and the sum of an arithmetic sequence from its first term and common difference. Free calculator with a preview of the sequence.
Geometric Sequence Calculator
Find the nth term, partial sum, and (if convergent) infinite sum of a geometric sequence from its first term and common ratio. Free and instant.
Inequality Calculator
Solve a one-variable linear inequality of the form ax + b [<,≤,>,≥] c and get the solution range for x, with correct sign-flip handling.
GPA Calculator
Calculate your GPA on the 4.0 scale with credit weighting: quality points, total credits and a letter-grade conversion table for the common US convention.
Grade Calculator
Work out your current weighted grade from assignment scores and weights, then find the exact score you need on the final exam to reach a target grade.
Area Calculator
Calculate the area of a circle, triangle, rectangle, trapezoid, parallelogram, ellipse, regular polygon or sector instantly with formulas shown.
Volume Calculator
Calculate the volume and surface area of a sphere, cube, box, cylinder, cone, pyramid, hemisphere or frustum instantly with formulas shown.
Surface Area Calculator
Calculate the total and lateral surface area of a sphere, cube, box, cylinder or cone instantly with formulas shown and verified.
Triangle Calculator
Solve any triangle from three sides, two sides and an included angle, or two right-triangle legs. Get area, perimeter and all angles instantly.
Pythagorean Theorem Calculator
Find a right triangle's hypotenuse or missing leg using the Pythagorean theorem (a² + b² = c²). Includes area, perimeter and worked examples.
Circle Calculator
Find a circle's radius, diameter, circumference and area from any one known value. Free, instant, formulas shown.
Arc Length Calculator
Calculate arc length, chord length, sector area and segment area from a circle's radius and central angle. Free, instant, formulas shown.
Distance Formula Calculator
Find the distance, midpoint and slope between two points (x1,y1) and (x2,y2) using the distance formula. Free, instant, worked examples.
Slope Calculator
Find the slope, angle of inclination and equation of the line through two points (x1,y1) and (x2,y2). Free, instant, worked examples.
Trigonometry Calculator
Calculate sine, cosine, tangent and their inverse functions in degrees or radians. Free, instant, with the complementary co-function shown.
Law of Sines Calculator
Solve a triangle from two angles and a side (AAS) using the law of sines. Get the missing side, third angle and area instantly.
Law of Cosines Calculator
Solve a triangle from two sides and the included angle (SAS) using the law of cosines. Get the missing side, both remaining angles and area.
Unit Circle Calculator
Find sine, cosine, tangent, reference angle and quadrant for any angle on the unit circle, in degrees or radians. Free and instant.
Derivative Calculator
Calculate the numerical derivative of a function at a point using a 5-point central difference method. Get f'(x0), f(x0) and the tangent line.
Integral Calculator
Calculate a definite integral numerically with adaptive Simpson's rule. Enter a function and bounds to get the integral value and average value.
Limit Calculator
Estimate a two-sided limit numerically by evaluating a function on both sides of an approach point. Get the left, right and two-sided limit.
GCF and LCM Calculator
Find the greatest common factor (GCF) and least common multiple (LCM) of two or more numbers, with the prime factorization of the GCF shown.
Factorial Calculator
Calculate n factorial (n!) exactly for n up to 18, or in scientific notation for n up to 170, plus trailing zero count and natural log of n!.
Permutation and Combination Calculator
Calculate permutations (nPr) and combinations (nCr) of n items taken r at a time, with and without repetition. Free calculator with clear examples.
Modulo Calculator
Calculate a mod b with both the floored (mathematical) and truncated (programming) sign conventions, plus the quotient and division equation.
Digital Root Calculator
Find the digital root of any whole number by repeatedly summing its digits until a single digit remains. Shows each step and the connection to mod 9.
Fibonacci Sequence Calculator
Find the nth Fibonacci number, the sum of the first n terms, and how the ratio of consecutive terms approaches the golden ratio. Free and instant.
Prime Factorization Calculator
Break any whole number down into its prime factors, with exponent notation, number of divisors and sum of divisors. Free and instant, up to 1 trillion.
Bitwise Operations Calculator
Perform bitwise AND, OR, XOR, NOT, left shift and right shift on two 32-bit integers. See binary representations and results instantly.