LCM Calculator

The least common multiple (LCM) is the smallest number that all the given numbers divide into exactly. It gives the common denominator for adding fractions and solves timing problems such as when two buses meet again.

Two or more whole numbers, separated by commas or spaces.
Results update as you type.

LCM

60

GCD (HCF) of the same numbers
2

About this calculator

Enter two or more whole numbers.

How to use it

  1. Enter the numbers, separated by commas.
  2. Read the LCM and GCD.

The formula

LCM(a, b) = a × b ÷ GCD(a, b)
GCD
greatest common divisor

Worked example

4, 6 and 10

  1. LCM(4, 6) = 12; LCM(12, 10) = 60.
  2. So the LCM is 60.

What the result means

Bells that ring every 4, 6 and 10 minutes ring together every 60 minutes.

Assumptions

  • Whole numbers.

Limitations

  • Results above 2⁵³ cannot be shown exactly.

Frequently asked questions

What is the LCM of 4 and 6?

12.

How do I find the LCM?

Divide the product by the GCD, or use prime factors.

Is LCM always larger than the numbers?

It is at least as large as the largest one.

Last reviewed on 3 October 2026. Found a mistake? Tell us.