Reduce Fraction Calculator

About this calculator

Reducing a fraction to lowest terms means dividing both the numerator and denominator by their greatest common divisor (GCD) — for example, 18/24 reduces to 3/4 because their GCD is 6 — most efficiently computed using the Euclidean algorithm, which repeatedly replaces the larger number with the remainder of dividing it by the smaller number until the remainder reaches zero.

A fully reduced fraction, also called being in “simplest form,” is the standard way fractions are expressed in math education, cooking measurements, engineering tolerances, and probability results, since an unreduced fraction like 15/45 conveys the same value as 1/3 but obscures the simpler relationship, making comparison, addition, and further calculation harder.

This calculator takes any numerator and denominator and returns the fraction reduced to its lowest possible terms.