# Greatest common factor calculator

### What is GCF?

The greatest common factor (gcf), or highest common factor (hcf), of two or more integers (at least one of which is not zero), is the largest positive integer that divides the numbers without a remainder. It is the highest number that divides exactly into two or more numbers. It is the "greatest" thing for simplifying fractions. The greatest common factor is useful for reducing fractions to be in lowest terms.