How the lcm calculator works
The Least Common Multiple of two numbers is calculated from their Greatest Common Factor:
LCM(a, b) = (a × b) / GCF(a, b)
For more than two numbers, the LCM is calculated pairwise: LCM(a, b, c) = LCM(LCM(a, b), c), and so on.
Step-by-step guide
- Enter two or more whole numbers, separated by commas.
- Read the Least Common Multiple instantly.
Worked example
For 4, 6 and 8: LCM(4,6) = 12, then LCM(12,8) = 24 — so 24 is the smallest number divisible by 4, 6 and 8 all at once.
Frequently asked questions
LCM is commonly used to find a common denominator when adding or subtracting fractions, and in scheduling problems (e.g. finding when two repeating events next coincide).
LCM is the smallest number divisible by all the given numbers; GCF (Greatest Common Factor) is the largest number that divides all of them evenly. See our GCF Calculator for the counterpart.
Yes — enter any number of comma-separated values and the calculator finds the LCM across all of them.