Calculate & Convert

GCF & LCM

Greatest common factor and least common multiple of a set of whole numbers.

Enter values

The formula

GCF via the Euclidean algorithm; LCM = a × b ÷ GCF

All calculations run locally in your browser and update instantly as you type.

Related calculators

Frequently asked questions

What are the GCF and LCM used for?+
The GCF simplifies fractions and ratios; the LCM finds common denominators and synchronises repeating cycles.
All calculations run locally in your browser. Nothing you type is sent to a server.