Find LCM and HCF/GCD of two or more numbers
Built & maintained by Pappu Venkata Subbi Reddy, founder of Clacify
LCM and HCF Calculator finds the Lowest Common Multiple and Highest Common Factor (also called GCD) of two or more numbers, with the steps shown. Enter your numbers to get both results, along with the prime factorisation used to reach them. HCF and LCM are core school maths topics and also appear in real problems like scheduling, fractions, and gear ratios. The step-by-step working helps students learn the method, not just the answer. Everything runs locally in your browser.
The HCF (highest common factor) is computed with the Euclidean algorithm — repeatedly replacing the larger number with the remainder of dividing the two, until one becomes zero. The LCM is then derived from the identity LCM(a, b) = (a × b) ÷ HCF(a, b), extended pairwise for more than two numbers. Prime factorisation is also shown to illustrate the method. All computation runs locally in your browser.
LCM (Least Common Multiple) is the smallest number that is a multiple of both. HCF/GCD (Highest Common Factor) is the largest number that divides both exactly. Example: LCM(12, 18) = 36. HCF(12, 18) = 6. Relationship: LCM × HCF = Product of the two numbers (12 × 18 = 36 × 6 = 216).
LCM: Adding/subtracting fractions with different denominators (find LCM of denominators), scheduling events that repeat at different intervals (buses, shifts), problems involving "when will they next coincide." HCF: Simplifying fractions to lowest terms, dividing objects into equal groups without remainder, finding the largest tile size to cover a floor exactly.