How is the LCM derived from the GCF?

For two numbers, LCM = (a × b) ÷ GCF(a, b). For more than two numbers, the calculator applies this pairwise across the full list, combining the running LCM with each next number.

Can I find the GCF/LCM of more than two numbers?

Yes, enter any comma-separated list of numbers and the calculator finds the GCF and LCM shared across all of them, not just pairs.

GCF & LCM Calculator

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

How this is calculated

GCF via the Euclidean algorithm; LCM = (a × b) ÷ GCF, extended across the full list

Assumptions used in this calculation

Algorithm: GCF is computed with the Euclidean algorithm; results are only defined for positive integers.

About this calculator

Finds the greatest common factor (GCF) and least common multiple (LCM) of two or more numbers, consolidating the master prompt's separate GCF and LCM calculators, since LCM is derived directly from GCF.

Worked example

12 and 18

Result: GCF = 6, LCM = 36

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About this calculator

Frequently asked questions

How is the LCM derived from the GCF?

Can I find the GCF/LCM of more than two numbers?

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