Add, subtract, multiply or divide two fractions

Simplify a single fraction

This free Fraction Calculator adds, subtracts, multiplies and divides fractions properly, the way maths classes teach it, and then tidy-ups the answer for you. Every result is automatically simplified to its lowest terms, converted into a mixed number when the top is bigger than the bottom, and also shown as a decimal, so you can check homework, scale a recipe, or split measurements without juggling three different conversions in your head. A second, smaller tool on the page simplifies a single fraction on its own and tells you the number it divided by.

Fractions trip people up because each operation has its own rule: adding needs a shared bottom number, multiplying goes straight across, and dividing means flipping the second fraction over. This calculator applies the right rule each time and reduces the answer by the greatest common divisor, so three sixths becomes one half instead of staying clumsy. It also guards against the classic impossible inputs, like a zero on the bottom, and explains the problem instead of guessing. Everything runs locally in your browser, so nothing you type is uploaded or stored.

How to use

Enter the top and bottom numbers of the first fraction.
Choose the operation: add, subtract, multiply or divide.
Enter the top and bottom numbers of the second fraction.
Click Calculate to see the simplified fraction, mixed number and decimal.
Use the second card when you only need to simplify one fraction.

Frequently asked questions

How do you add fractions with different bottom numbers?

You first rewrite both fractions over a common denominator. One reliable way is to multiply each top and bottom by the other fraction's bottom number, add the tops, then simplify. That is exactly what this calculator does behind the scenes.

What is a mixed number?

It is a whole number together with a proper fraction, such as one and a half instead of three halves. Mixed numbers are easier to picture for cooking and measuring, which is why the calculator shows them whenever the result is bigger than one.

Why simplify a fraction at all?

The simplest form is the standard way to present an answer, and it is much easier to compare with other fractions. Two quarters and one half are the same value, but the simpler version is clearer and is what teachers and exams expect.

Can the calculator handle negative fractions?

Yes. Put the minus sign on the top number and the calculation, simplification and decimal all keep the correct sign. The answer is always presented with any negative sign in the standard position.