Least Common Multiple Calculator

Use this free least common multiple calculator to find the LCM of two or more positive whole numbers with exact integer math, examples, copy, history, and step-by-step notes.

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Two or more numbers Exact LCM Common denominators Copy results
Least common multiple180
Numbers checked
3
Smallest input
12
Largest input
30

Steps

  1. Start with 12, 18, 30.
  2. Use each pair GCF to combine numbers without losing exact integer precision.
  3. For two numbers, LCM(a,b) = a x b / GCF(a,b).
  4. The least common multiple is 180.

How to use the least common multiple calculator

  1. Enter at least two positive whole numbers separated by commas, spaces, or semicolons.
  2. Press Calculate LCM to find the smallest shared positive multiple.
  3. Review the exact answer, input range, and LCM steps.
  4. Use examples, recent answers, or copy answer while checking fraction or schedule problems.

Common uses

Find a common denominator before adding or comparing fractions.

Solve schedule problems where events repeat at different intervals.

Check school math problems involving multiples and divisibility.

Compare two or more positive whole numbers with exact integer results.

Examples

Three numbers LCM of 12, 18, 30

180

Two numbers LCM of 8 and 14

56

Common denominator LCM of 6, 15, 25

150

Frequently asked questions

Quick answers about shared multiples, common denominators, positive integers, LCM steps, and privacy.

What is the least common multiple?

The least common multiple is the smallest positive number that is a multiple of every number in the list.

How does the LCM Calculator find the answer?

It combines the numbers with the relationship LCM(a,b) = a x b / GCF(a,b). That keeps the answer exact while it moves through the list.

Can I enter more than two numbers?

Yes. Enter at least two positive whole numbers separated by commas, spaces, or semicolons. The calculator finds one LCM for the whole list.

Why do the inputs need to be positive whole numbers?

LCM is normally used for positive integers. Zero and negative values make the idea of the smallest positive shared multiple unclear for this everyday calculator.

When should I use the Greatest Common Factor Calculator instead?

Use GCF when you need the largest shared divisor. Use LCM when you need the smallest shared multiple, such as a common denominator.

Is my LCM history private?

Yes. Recent LCM answers stay only in the current browser tab while you use the page. They are not sent to a server.

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