How to Simplify Fractions
5 min read · Updated September 26, 2026 · by the SolveCalcPro editorial team
A fraction is simplified (in lowest terms) when the top and bottom share no common factor except 1. 6/8 and 3/4 are the same value, but 3/4 is the simplest form. There are two easy ways to get there.
Method 1: divide by the GCF
Find the greatest common factor of the numerator and denominator and divide both by it.
18/24: factors of 18 are 1, 2, 3, 6, 9, 18 and of 24 are 1, 2, 3, 4, 6, 8, 12, 24. The GCF is 6, so 18/24 = 3/4.
84/126: GCF = 42, so 84/126 = 2/3. For bigger numbers, use the GCF calculator.
Method 2: divide by small primes repeatedly
If you cannot see the GCF, divide by any common factor, then repeat until no common factor remains. 84/126 ÷ 2 = 42/63, then ÷ 3 = 14/21, then ÷ 7 = 2/3.
Divisibility tests
| Divisible by | Test |
|---|---|
| 2 | Last digit even |
| 3 | Digits add to a multiple of 3 |
| 5 | Ends in 0 or 5 |
| 9 | Digits add to a multiple of 9 |
| 10 | Ends in 0 |
Special cases
- If the numerator is 0, the fraction is 0.
- If the numerator and denominator are equal, it is 1.
- If the numerator is bigger, convert to a mixed number: 17/5 = 3 2/5.
- A negative sign can sit in front: −6/8 = −3/4.
Practice questions
Test yourself, then tap to check. Answers are calculated by the tools linked below.
- Find the GCF and LCM of 18 and 24.
Show answer
GCF (greatest common factor): 6 · LCM (least common multiple): 72
- Add 2/3 + 3/4.
Show answer
Simplified fraction: 17/12
- Is 221 prime?
Show answer
Is 221 prime?: No, composite
Frequently asked questions
How do I know if a fraction is fully simplified?
If the GCF of the numerator and denominator is 1, it is in lowest terms.
Does simplifying change the value?
No. You divide top and bottom by the same number, which is the same as dividing by 1.
How do I simplify a fraction with decimals?
Multiply the top and bottom by a power of 10 to remove the decimals first, then simplify.
Is 4/9 simplified?
Yes. 4 and 9 share no factor other than 1.
Try it yourself
GCF and LCM CalculatorFind the greatest common factor and least common multiple of up to 8 numbers.
Fraction CalculatorAdd, subtract, multiply and divide fractions with simplified and mixed-number answers.Prime Number CheckerTest whether a number is prime and see its factorization and neighbouring primes.Keep learning
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