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LCM & GCF Calculator — Instant Answers
Stuck on fractions, multiples or factors homework? This free LCM calculator finds the least common multiple of your numbers instantly — and the GCF (greatest common factor) too.
Enter two or more numbers separated by spaces or commas. The calculator shows the LCM you need for adding fractions with different denominators, plus the GCF for simplifying them.
Students: use it to check your hand-worked answers, not to skip learning the method — exams still want the steps.
LCM & GCF Calculator — Least Common Multiple & Greatest Common Factor
Free LCM calculator and GCF calculator (also called HCF — highest common factor) for school maths and homework: enter two or more whole numbers separated by commas and get the LCM and GCF together, with the maths shown step by step.
Common questions
What is LCM?
The least common multiple (LCM) is the smallest number that all your numbers divide into evenly. Example: the LCM of 4 and 6 is 12.
What is the difference between LCM and GCF?
LCM is the smallest number your numbers all divide into; GCF (greatest common factor, also called HCF) is the largest number that divides all of them. This calculator gives you both.
Can I find the LCM of three or more numbers?
Yes. Enter as many numbers as you like, separated by spaces or commas, and the calculator handles all of them.
Why do students need LCM?
Adding or subtracting fractions with different denominators needs a common denominator — the LCM of the denominators is the smallest one that works.