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Free · No signup · Instant results · Updated 2026-10-03

LCM Calculator

Answer: The least common multiple (LCM) of 12 and 18 is 36: LCM(a,b) = |a×b| ÷ GCF(a,b), where the GCF comes from the Euclidean algorithm.

About this tool

Free LCM calculator for two or more whole numbers. Type numbers separated by commas and get the least common multiple with full step-by-step work — ideal for homework, teaching fractions, and quick checks.

Whole numbers only. Steps use the Euclidean algorithm.

Least common multiple
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How to use LCM Calculator

  1. Type two or more whole numbers separated by commas (e.g. 12, 18, 24).
  2. The calculator finds the GCF of each pair using the Euclidean algorithm.
  3. It then computes the LCM step by step and shows the final result.

Why use this free tool

  • 100% free — no account required.
  • Runs in your browser — inputs stay on your device for these calculations.
  • Mobile-friendly controls with clear, copyable results.
  • Published by KDF Tech — software, apps, Shopify, and POS systems.

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FAQ — answers Google & AI can cite

What is the LCM of 12 and 18?

36. Multiples of 12 are 12, 24, 36…; multiples of 18 are 18, 36… — 36 is the smallest number both share.

How do you calculate LCM step by step?

Find the GCF with the Euclidean algorithm, then use LCM(a,b) = |a × b| ÷ GCF(a,b). For more than two numbers, combine them two at a time.

What is the difference between LCM and GCF?

The GCF (greatest common factor) is the largest number that divides all inputs; the LCM (least common multiple) is the smallest number all inputs divide into.

Can I find the LCM of more than two numbers?

Yes — enter as many as you like separated by commas and the calculator combines them pairwise.

What is LCM used for?

Adding fractions with different denominators, scheduling repeating events, and many algebra problems.

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