LCM Calculator
Find the least common multiple of two numbers in one click.
Find the least common multiple (LCM) of two numbers instantly — the smallest number both divide into evenly. Essential for adding fractions with different denominators, scheduling repeating events, and number-theory homework.
How it's calculated
The LCM is computed as |a × b| ÷ GCF(a, b), using the Euclidean algorithm for the GCF — fast and exact for any integers.
Frequently asked questions
What is the LCM of 12 and 18?
36. It's the smallest number both 12 and 18 divide into evenly (12 × 3 = 36, 18 × 2 = 36).
When do I need the LCM?
Most often when adding or subtracting fractions with different denominators — the LCM of the denominators is the common denominator to use.
What is the difference between LCM and GCF?
The LCM is the smallest number both numbers divide into; the GCF is the largest number that divides both. For 12 and 18, the LCM is 36 and the GCF is 6.