Math Tools
Fraction, ratio, average, standard deviation, prime, GCD/LCM, quadratic, permutation, Roman numeral, triangle and base-conversion calculators — instant, accurate and free.
Fraction Calculator
Add, subtract, multiply and divide two fractions online. Get the result as an improper fraction, a simplified fraction, a mixed number and a decimal.
Fraction Simplifier
Reduce any fraction to its lowest terms online. See the greatest common divisor used, the simplified fraction, the mixed number and the decimal value.
Decimal to Fraction Converter
Convert a decimal to a fraction online. Handles terminating and repeating decimals, and returns the exact fraction, simplified form and mixed number.
Ratio Calculator
Simplify a ratio to its lowest terms or solve a proportion A:B = C:? to find the missing value. Free online ratio calculator with clear working.
Average Calculator
Calculate the mean, median, mode, range, sum, count, minimum and maximum of a list of numbers. Free online average calculator with instant results.
Standard Deviation Calculator
Calculate population and sample standard deviation and variance from a list of numbers. Free online tool showing the mean, count and formula steps.
Prime Number Checker
Check whether a number is prime or composite. See the smallest factor and the full list of factors for any integer up to billions, instantly and privately.
Prime Factorization Calculator
Find the prime factorization of any integer. See the prime factors with exponents and the product form like 2² × 3 × 5, calculated instantly in your browser.
GCD & LCM Calculator
Find the greatest common divisor (GCD) and least common multiple (LCM) of two or more integers using Euclid's algorithm, with the working shown.
Quadratic Equation Solver
Solve any quadratic equation ax² + bx + c = 0. Get real or complex roots, the discriminant, vertex and axis of symmetry with clear step-by-step working.
Permutation & Combination Calculator
Calculate permutations (nPr) and combinations (nCr) instantly from n and r, with the factorial formulas shown. Free online nPr and nCr calculator.
Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers (1–3999). Free two-way Roman numeral converter with input validation.
Number to Words Converter
Convert numbers to words in English, including decimals, negatives and a currency mode for dollars and cents. Free online number-to-words spelling tool.
Factorial Calculator
Calculate the factorial of any number (n!) exactly using BigInt, and see the full result plus its digit count. Free online factorial calculator.
Percentage to Fraction Converter
Convert between percentages, fractions and decimals instantly, with the fraction fully simplified. Free online percent to fraction and decimal converter.
Triangle Solver
Solve any triangle from known sides and angles (SSS, SAS, ASA, AAS, SSA) using the laws of sines and cosines. Get all sides, angles, area and perimeter.
Pythagorean Theorem Calculator
Solve the Pythagorean theorem: enter any two sides of a right triangle to find the third, plus the area. Free a² + b² = c² calculator with steps.
Slope Calculator
Find the slope, midpoint, distance, line equation and angle of incline from two points. Free slope calculator that handles vertical lines too.
Number Base Converter
Convert whole numbers between any bases from 2 to 36, with from-base and to-base selectors and digit validation. Free online number base converter.
Rounding Calculator
Round any number to decimal places, significant figures or the nearest multiple, with round, floor and ceiling modes. Free online rounding calculator.