GCF and LCM calculator
The greatest common factor and least common multiple of any whole numbers, worked out from their prime factors.
How it’s worked out
Questions people ask
What is the difference between GCF and LCM?
The GCF is the largest number that divides all of them. The LCM is the smallest number all of them divide into. For 12 and 18, the GCF is 6 and the LCM is 36.
When do I use the LCM?
To find a common denominator when adding fractions, or when two repeating things line up again: buses every 12 and 18 minutes leave together every 36 minutes.