The greatest common divisor (GCD, also called HCF in Indian textbooks) is the largest number that divides both inputs. The least common multiple (LCM) is the smallest positive number that both divide into. For two numbers they are linked by LCM(a, b) = a × b ÷ GCD(a, b). For 12 and 18, the GCD is 6 and the LCM is 36. This calculator takes two positive whole numbers and uses Euclid's algorithm to find their GCD, then derives the LCM. It is useful for simplifying fractions, finding a common denominator for two fractions and comparing two repeating schedules.
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