Fraction calculator
Add, subtract, multiply and divide, then simplify.
About this calculator
Enter two fractions and choose an operation. The answer is simplified automatically, and shown as a mixed number and a decimal where that helps.
Use whole numbers for the top and bottom of each fraction. For a mixed number such as 1 1/2, enter it as 3/2.
How it works
Fractions are put over a common denominator where needed, then divided by their greatest common divisor.
Worked example
- First top: 2
- First bottom: 3
- Operation: +
- Second top: 3
- Second bottom: 4
Answer: 17/12
The story behind it
Where the idea came from: Ancient Egyptian scribes, recorded around 1550 BC.
Fractions are among the oldest maths on record. The Rhind Papyrus, copied by the Egyptian scribe Ahmes around 1550 BC, is full of them, mostly written as sums of unit fractions such as 1/2 + 1/4. The bar we use today came much later, through Arabic mathematicians. Adding and simplifying them by hand still trips people up, so this calculator gives the answer in lowest terms.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, so please double-check anything important.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
Meet the founder