LCM Calculator

Lowest common multiple, computed without overflowing.

Lowest common multiple, computed without overflowing. The lowest common multiple of two or more numbers.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

First number

Second number

Third number

Optional.

Fourth number

Optional.

Lowest common multiple

GCF is 6

Numbers12, 18

Greatest common factor6

Lowest common multiple36

All common factors1, 2, 3, 6

Simplified ratio2 : 3

CoprimeNo

The GCF and LCM are linked: for two numbers, GCF × LCM equals the product of the numbers themselves. Here 6 × 36 accounts for every prime factor exactly once between them — the GCF taking the shared ones and the LCM the union.

How the LCM Calculator works

The lowest common multiple of two or more numbers. It is computed as a ÷ gcf × b rather than a × b ÷ gcf, so the intermediate value stays small — the obvious ordering overflows on inputs whose product is large even when the answer is not.

Also known as: lowest common multiple · least common multiple calculator · common denominator calculator · lcm of two numbers

Where to go next

The LCM question rarely arrives on its own. These are the ones that usually come with it:

GCF Calculator — Greatest common factor, with every common factor listed.
Prime Factorization Calculator — Prime factors, the divisor count, and where it comes from.
Fraction to Decimal Calculator — Decimal, percentage, and whether it terminates.
Percentage Calculator — Every common percentage question in one place.

Sources

NIST Digital Library of Mathematical Functions

Frequently asked questions

How do I find the lowest common multiple?

Divide the product of the numbers by their greatest common factor. For 4 and 6 that is 24 ÷ 2 = 12.

What is the LCM used for?

Most often finding a common denominator when adding fractions. It is also what determines when two repeating cycles line up again.

Is the LCM always the product of the numbers?

Only when they are coprime. If they share factors, the LCM is smaller — 4 and 6 have an LCM of 12, not 24.

Can I find the LCM of more than two numbers?

Yes — take them in pairs, LCM the first two, then LCM that result with the next. This page accepts up to four.

Put this calculator on your own site

Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.

The one-line version

<iframe src="https://www.thecalclibrary.com/embed/lcm-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="LCM Calculator"></iframe>
<p style="font:13px/1.5 system-ui,sans-serif;margin:6px 0 0;color:#64748b">Powered by <a href="https://www.thecalclibrary.com/lcm-calculator" style="color:#64748b">LCM Calculator</a> from The Calc Library</p>

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