Math calculators
Percentages, ratios, fractions and other everyday math worked out instantly.
Compound Rule of Three Calculator
Free compound rule of three calculator — solve a proportion problem driven by two supplementary variables (each direct or inverse). Works in your browser.
Final Grade Needed Calculator
Free "what do I need on the final?" calculator — enter your current grade, final exam weight and target overall to see the score required.
Fraction Calculator
Free fraction calculator — add, subtract, multiply or divide two fractions. The result is shown in lowest terms with the decimal value. Works in your browser.
LCM and GCD Calculator
Free LCM (least common multiple) and GCD (greatest common divisor) calculator — type a list of integers, get both at once. Works in your browser.
Mean, Median and Mode Calculator
Free mean, median and mode calculator — paste any list of numbers and get all three at once, plus a quick read on whether the data are skewed.
Percentage Calculator
Free percentage calculator — find X% of a number, work out what percent one number is of another, or calculate a percentage increase or decrease. Instant, works in your browser, no sign-up.
Quadratic Equation Solver
Free quadratic equation solver — enter a, b, c and get both roots using the quadratic formula (Bhaskara). Handles real, repeated and complex roots.
Rule of Three Calculator
Free rule-of-three calculator (cross multiplication) — direct and inverse proportion. Enter three known values, get the fourth. Works in your browser.
Weighted Average Calculator
Free weighted average calculator — combine values with their weights in one step. Great for grades, GPAs and any weighted score. Works in your browser.