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Least Common Multiple Calculator

Find the least common multiple of any set of numbers, with steps.

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LCM Calculator

Least common multiple of a set of numbers

Separate with commas or spaces.

LCM(12, 18, 30)

180

Next common multiples
360, 540, 720

How it was calculated

  1. 12 = 2² × 3
  2. 18 = 2 × 3²
  3. 30 = 2 × 3 × 5
  4. Take each prime at its highest power: 2² × 3² × 5
  5. LCM = 2² × 3² × 5 = 180

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How the lcm calculator works

The least common multiple is the smallest positive number that every number in the set divides into evenly. It's what you need to add fractions with different denominators (the least common denominator).

Prime factorization method: factor each number, then multiply every prime that appears, using its highest power. For 12 = 2² × 3, 18 = 2 × 3² and 30 = 2 × 3 × 5, the LCM is 2² × 3² × 5 = 180. For two numbers there's a shortcut: LCM(a, b) = a × b / GCF(a, b).

Using and checking your result

Published by JustYourCalculator. Check the units and assumptions above, and compare a known example before relying on the output. Calculations use browser arithmetic and may round displayed values.

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