GCD and LCM Calculator

Find the greatest common divisor (GCD/HCF) and least common multiple (LCM) of two or more integers of any size.

How to use the GCD and LCM Calculator

Enter or select: Integers.
The results (GCD (HCF), LCM) are calculated instantly as you type.
Use “Copy link” to share the calculation with the same input values.

Formula

gcd(a, b) = gcd(b, a mod b)
lcm(a, b) = |a·b| / gcd(a, b)

About this tool

Uses the Euclidean algorithm with arbitrary-precision integers.