Least Common Multiple Calculator

Find the smallest number divisible by both inputs

First Number

Second Number

About this calculator

The Least Common Multiple (LCM) of two numbers is the smallest positive integer divisible by both. LCM(12, 18) = 36. It is calculated using the relationship: LCM(a,b) = (a × b) / GCF(a,b). LCM is essential for adding fractions with different denominators and solving problems involving repeating cycles.

How to use

LCM(4, 6) = 12. This means if one event repeats every 4 days and another every 6 days, they coincide every 12 days. Also useful: to add 1/4 + 1/6, the common denominator is LCM(4,6) = 12.

Frequently asked questions

What is the relationship between LCM and GCF?

LCM(a,b) × GCF(a,b) = a × b. They are mathematically linked. If you know one, you can find the other.

When would LCM equal one of the input numbers?

When one number is a multiple of the other. LCM(6, 12) = 12, because 12 is already divisible by 6.