How to Simplify Fractions (Step by Step)

The idea: divide by the GCD

To simplify, divide the numerator (top) and denominator (bottom) by their greatest common divisor (GCD) — the largest number that divides both exactly.

Example: for 8/12, the GCD of 8 and 12 is 4. Divide both by 4: 8 ÷ 4 = 2 and 12 ÷ 4 = 3, giving 2/3. That is fully simplified because 2 and 3 share no common factor above 1.

Finding the GCD

List the factors of each number and take the biggest they share, or use the quick rule: keep dividing both numbers by any common factor (2, 3, 5…) until none is left. The GCD & LCM Calculator finds it instantly for any pair.

A worked example

Simplify 18/24. The GCD of 18 and 24 is 6. 18 ÷ 6 = 3 and 24 ÷ 6 = 4, so 18/24 = 3/4. You can also do it in steps: divide both by 2 to get 9/12, then by 3 to get 3/4 — same answer.

Let the tool do it

The Fraction Simplifier reduces any fraction to lowest terms and also shows it as a decimal and a percentage. Enter the numerator and denominator and read the simplest form.