GCD and LCM Calculator

Calculate greatest common divisor and least common multiple of two integers.

GCD & LCM Calculator helps you find the greatest common divisor and least common multiple of two integers. Enter first whole number (a) and second whole number (b), review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the GCD / LCM calculator does GCD & LCM Calculator is built for arithmetic, algebra, geometry, and number tools. Find the greatest common divisor and least common multiple of two integers. You enter first whole number (a) and second whole number (b), then Simple Calculators computes the result instantly. Results use standard school and engineering formulas that run privately in your browser. How the math works The GCD comes from repeated division (Euclid’s method): divide the larger number by the smaller, then divide the smaller by the remainder, and so on until the remainder is 0. Then LCM = (a × b) ÷ GCD. The formula: LCM = (a × b) ÷ GCD. GCD: divide the larger number by the smaller, then the smaller by the remainder, until the remainder is 0.