GCD & LCM Calculator
Find the greatest common divisor (GCD) and least common multiple (LCM) of two whole numbers.
Result
GCD (greatest common divisor)
6
LCM (least common multiple)
36
How it works
LCM = (a × b) ÷ GCD
The GCD is the largest number that divides both; the LCM is the smallest number both divide into. Example: 12 and 18 → GCD 6, LCM 36.
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Frequently asked questions
How is the GCD found?
By Euclid's algorithm: repeatedly replace the larger number by the remainder of the division until one is zero.
How are GCD and LCM related?
For any two numbers, GCD × LCM = a × b.
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