LCM of Two Numbers Calculator

Enter two whole numbers to find their least common multiple, with the steps shown.

Finding the LCM of two numbers

With two numbers, the quickest route is the formula LCM(a, b) = (a × b) ÷ GCD(a, b). For 8 and 12, the GCD is 4, so the LCM is (8 × 12) ÷ 4 = 96 ÷ 4 = 24.

You can also list multiples. Multiples of 8: 8, 16, 24, 32. Multiples of 12: 12, 24, 36. The first number in both lists is 24.

Good to know

If the two numbers share no factors, multiply them. LCM(9, 10) = 90.
If the smaller number divides the larger one, the LCM is the larger number. LCM(5, 15) = 15.
The LCM is never smaller than the bigger of your two numbers.