Maths calculators
Free calculators that show their working, so you can check your own answers and see how each one is done. Everything runs in your browser.
Choose a calculator
Percentage Calculator
Free percentage calculator: find X% of a number, what percent one number is of another, or the whole when you know a part.
Percent Change Calculator
Free percent change calculator: percent increase or decrease between two numbers, a number after a percent rise or fall, and the original before a change.
Ratio Calculator
Free ratio calculator: simplify a ratio, solve a proportion (a : b = c : ?), or split an amount in a ratio.
Compound Interest Calculator
Free compound interest calculator with regular deposits, plus simple interest.
Work and Time Calculator
Free work and time calculator: how long people or machines take working together, a missing worker's time, or a tank filling while it drains.
Speed, Distance and Time Calculator
Free speed, distance and time calculator: find any one from the other two, or the average speed for a round trip or two legs.
Fraction Calculator
Free fraction calculator: add, subtract, multiply and divide fractions and mixed numbers.
GCD and LCM Calculator
Free GCD (HCF) and LCM calculator for two to six numbers, with prime factorisations and the Euclidean algorithm shown step by step.
Prime Factorization Calculator
Free prime factorization calculator: break any whole number into prime factors, check if it is prime, and see its divisors, with the steps shown.
Mean, Median, Mode Calculator
Free mean, median, mode and range calculator with standard deviation, variance and quartiles for a list of numbers.
Quadratic Equation Solver
Free quadratic equation solver: find real or complex roots of ax² + bx + c = 0 using the quadratic formula, with the discriminant, vertex and steps shown.
Permutation and Combination Calculator
Free permutation and combination calculator (nPr and nCr), with repetition allowed or not, exact for large numbers, with the formulas shown.
Number to Words Converter
Free number to words converter: write any number in English words, with American or British style and the Indian lakh and crore system.
Roman Numerals Converter
Free Roman numerals converter: turn numbers from 1 to 3999 into Roman numerals and back, with the steps shown and a check for invalid numerals.
Calculators are for learning and quick checks. Do not rely on them for tax, legal or financial decisions.