GCF Calculator

The largest number that divides evenly into a whole list of numbers.

Works with any number of positive whole numbers, not just two.

Greatest common factor
6

The largest number that divides evenly into all your inputs — useful for simplifying fractions to lowest terms.

A worked example

The GCF of 12, 18 and 24 is 6 — the largest number that divides evenly into all three.

Frequently asked questions

Is GCF the same thing as GCD?

Yes — greatest common factor and greatest common divisor are two names for the exact same value, just different terminology depending on the textbook or region.

How does GCF help simplify a fraction?

Dividing both the numerator and denominator by their GCF reduces the fraction to its lowest terms in one step, rather than dividing by smaller common factors repeatedly.