Overview
The least common multiple of two numbers is the smallest number divisible by both. For example, the multiples of 4 are 4, 8, 12, 16... and the multiples of 6 are 6, 12, 18...; the least common multiple is 12.
Formula
LCM(a, b) = |a × b| ÷ GCD(a, b).
How it works
Enter the numbers
Use positive integers separated by commas.
Calculate the GCD
The greatest common divisor is used in the formula.
Read the LCM
The least common multiple appears with each number's factorization.
Worked examples
Example 1: 4 and 6
LCM(4, 6) = 12, because 12 is divisible by both 4 and 6.
Example 2: 3, 5 and 7
LCM = 105, because the numbers are pairwise coprime.
Frequently asked questions
Can zero be used?
No. Positive integers are required because the LCM is not defined for zero in this form.
Is the LCM always larger than the numbers?
Not always. If one number is a multiple of the other, the LCM can equal the larger number.
How is the LCM related to the GCD?
The product of the two numbers equals LCM × GCD.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.