GCF and LCM Calculator

Find the greatest common factor and least common multiple of two numbers.

First number:

Second number:

How to use

Enter two whole numbers and click Calculate. Everything runs in your browser — nothing is uploaded or stored.

What are the GCF and LCM of 12 and 18?

GCF is 6, LCM is 36.

Does it work with big numbers?

Yes, up to about 15 digits.

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