About the Simplify Fraction Calculator
A fraction is in simplest form, or lowest terms, when the top and bottom share no common factor except 1. To reduce one, you divide both numbers by their greatest common divisor. This calculator finds that divisor for you, shows the simplified fraction and tells you which number it divided by. It also gives the mixed number for improper fractions, the decimal value and the percentage. Negative signs are moved to the top, and fractions that are already simple are labelled as such, so you can use it to check your own homework answers.
Updated October 2026
How to use the Simplify Fraction Calculator
- 1Type the numerator, the top number, in the first box.
- 2Type the denominator, the bottom number, in the second box.
- 3Read the simplified fraction in the result box.
- 4Look at the divisor line to see what both numbers were divided by.
- 5Use the mixed number, decimal and percent lines if you need another form.
Why simplifying matters
Simple fractions are easier to compare, add and understand. 6/8 and 3/4 are the same amount, but 3/4 is quicker to picture. Teachers usually expect final answers in lowest terms, and some tests mark an unsimplified fraction as incomplete.
Reduced fractions also make arithmetic safer. When you add 5/6 and 7/12, converting to a shared denominator is easier if both fractions are already simple. Large numerators and denominators tend to appear after multiplication, for example 14/21 times 9/12 gives 126/252, which collapses to 1/2 once reduced. Working in lowest terms keeps numbers small and mistakes rare, and it lets you see at a glance whether two answers are equal.
Quick checks before you reach for a tool
- If both numbers are even, divide by 2.
- If the digits of both add up to a multiple of 3, divide by 3.
- If both end in 0 or 5, divide by 5.
- If one number divides the other exactly, the smaller one is the divisor.
Moving on from simplification
Once your fraction is simple, you can add or multiply it with the Fraction Calculator, convert it with the Decimal to Fraction Converter or find shared factors with the GCF and LCM Calculator. The Proportion Calculator helps when two fractions have to be equal.
Features
- Reduces to lowest terms with the GCD
- Shows the divisor used
- Improper fraction to mixed number
- Decimal and percent forms
- Handles negative numerators and denominators
- Rejects a zero denominator with a clear message
Frequently asked questions
How do I simplify a fraction?
Find the largest number that divides both the top and bottom, then divide both by it. For 18/24 the largest shared factor is 6, so the fraction becomes 3/4. Repeat until no common factor above 1 is left.
What is the greatest common divisor?
It is the largest whole number that divides two numbers without a remainder. The Euclidean method finds it quickly by repeatedly taking remainders. The calculator uses it to reduce the fraction in a single step.
How do I turn an improper fraction into a mixed number?
Divide the top by the bottom. The whole-number part of the answer is the integer, and the remainder goes over the original bottom number. 17/5 is 3 with a remainder of 2, so it is 3 and 2/5.
Can I simplify a fraction with decimals?
Not directly. Multiply the top and bottom by the same power of 10 until both are whole numbers. 1.5/2.5 becomes 15/25, which simplifies to 3/5.
Why is my fraction already in lowest terms?
If the numerator and denominator are coprime, meaning they share no factor other than 1, nothing can be cancelled. Fractions like 7/9 and 5/12 are already simple, and the calculator labels them so.
Where does the minus sign go?
By convention it goes in front of the whole fraction or on the top number. The calculator writes −1/2 rather than 1/−2, and a negative on both sides cancels out.