GCF & LCM Calculator
Greatest common factor and least common multiple of two numbers.
- Greatest common factor (GCF)6
- Least common multiple (LCM)36
Inputs used
- First number12
- Second number18
About this calculator
The greatest common factor (GCF, also called GCD or HCF) is the largest number that divides both values exactly: for 12 and 18 it's 6. The least common multiple (LCM) is the smallest number both divide into: for 12 and 18 it's 36.
The two are linked: GCF × LCM = the product of the two numbers, which is how this calculator's results always multiply back to your inputs. GCF is what you use to simplify fractions; LCM is what you need to add them — the least common denominator is exactly the LCM of the denominators.
Numbers whose GCF is 1 (like 8 and 15) are called coprime — they share no factors, and their LCM is simply their product.
Results are informational only — not financial, medical or legal advice.