The Excel LCM function returns the least common multiple — the smallest positive whole number that every supplied value divides into evenly.
Syntax
| Argument | Description | |
|---|---|---|
number1 | Required | The first value. Non-integers are truncated to integers; negatives are not allowed. |
number2, ... | Optional | Up to 254 additional values. LCM finds the smallest multiple shared by all of them. |
How to use it
LCM (least common multiple) finds the smallest number that all the arguments divide into without a remainder.
The classic use is finding a common denominator when adding fractions, or working out when repeating cycles line up again (every 4 days and every 6 days coincide every 12 days). LCM is the partner of GCD.
GCD and LCM are linked: for two numbers, GCD(a,b) * LCM(a,b) = a * b. So once you know one, the other follows.
Try it: interactive demo
Pick a LCM example to see the formula and its result.
Practice workbook
Frequently asked questions
What is the least common multiple?
=LCM(4,6) = 12 because 12 is the smallest number both 4 and 6 divide into.Can LCM take more than two numbers?
=LCM(6,8,12) = 24, the smallest multiple shared by all three.How is LCM useful with fractions?
How are LCM and GCD related?
GCD(a,b) * LCM(a,b) = a * b. They are complementary measures of shared factors.Master functions like this in one day
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