LCM & GCF Calculator
Find the Least Common Multiple (LCM) and Greatest Common Factor (GCF/GCD) of two numbers.
Formula
GCF = greatest number that divides both — LCM = (a × b) ÷ GCFLCM & GCF Explained
The Greatest Common Factor (GCF) is the largest number that divides both numbers evenly. The Least Common Multiple (LCM) is the smallest number that both numbers divide into evenly. They're related: LCM(a,b) = (a × b) ÷ GCF(a,b).
Frequently Asked Questions
When do I use LCM?
LCM is used to find common denominators when adding fractions, and to find when events with different cycles will coincide.
When do I use GCF?
GCF is used to simplify fractions, reduce ratios, and distribute items into groups evenly.