LCM and GCF calculator
Enter two or more whole numbers separated by commas or spaces.
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How it is calculated
The GCF is the largest number that divides all of them; the LCM is the smallest number that is a multiple of all of them.
LCM(a, b) = a × b / GCF(a, b)
Using prime factors: the GCF takes the common factors with the lowest exponent, and the LCM takes every factor with the highest exponent.
Frequently asked questions
What is the LCM of 12, 18 and 30?
180; their GCF is 6.
What is the LCM used for?
To add fractions with different denominators or to find when two cycles line up again.