GCD & LCM Calculator
Find the greatest common divisor and least common multiple of numbers.
GCD (HCF)
6
LCM
72
GCD and LCM, explained
The greatest common divisor (GCD, also called HCF) is the largest number that divides every value evenly — useful for simplifying fractions and ratios. The least common multiple(LCM) is the smallest number all values divide into — handy for adding fractions and aligning repeating cycles. This calculator uses Euclid's algorithm for the GCD and derives the LCM as a ÷ gcd × b, applied across the whole list.
More number tools: the prime number checker, the percentage calculator, and the base converter.
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