GCF & LCM Calculator
Enter two or more integers to find their greatest common factor (GCF) and least common multiple (LCM).
Positive integers, comma or space separated.
- GCF6
- LCM72
Results are estimates for general information only and are not professional financial, medical, tax, or legal advice. Read the full disclaimer.
How it works
GCF via Euclid's algorithm. LCM(a, b) = |a·b| / GCF(a, b).
GCF(12, 18) = 6. LCM(12, 18) = 36.
Frequently asked questions
- Is GCF the same as HCF?
- Yes — GCF and HCF (highest common factor) are identical.
- Why is LCM useful?
- Adding fractions requires a common denominator — the LCM of the denominators.
- Do negatives matter?
- Sign is ignored — GCF and LCM are defined as non-negative.
- More than two numbers?
- Yes — apply GCF/LCM pairwise across the list.
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