GCF & LCM Calculator
Enter two or more whole numbers to get their greatest common factor and least common multiple.
Reviewed by the OmniCalc teamMethod verified 2026-07-01
GCF 6
= LCM 72
GCF 6, LCM 72Show steps
- Numbers: 12, 18, 24.
- GCF (greatest common factor) = 6.
- LCM (least common multiple) = 72.
How to use the GCF & LCM calculator
- 1Type your numbers, separated by commas or spaces (for example 12, 18, 24).
- 2Read the GCF and LCM for the whole list.
- 3Open Show steps for a plain restatement of the result.
Where it helps
The GCF reduces fractions to lowest terms; the LCM is the common denominator when adding fractions with different denominators. Try the fraction calculator to see both in action.
Frequently asked questions
What is the difference between GCF and LCM?
The greatest common factor (GCF) is the largest number that divides every value evenly. The least common multiple (LCM) is the smallest number that every value divides into. For 12 and 18, the GCF is 6 and the LCM is 36.
How many numbers can I enter?
As many as you like — separate them with commas or spaces. The GCF and LCM are computed across the whole list at once.
Does the sign matter?
No. Factors and multiples are about magnitude, so the calculator uses the absolute value of each number. Zeros are not allowed because every number divides zero.