Fraction Calculator

The fraction calculator is a free tool that runs entirely in your browser, with no data ever sent to a server. Add, subtract, multiply or divide two fractions.

Adding two fractions

Addition needs a common denominator. Three quarters plus five sixths become nine twelfths plus ten twelfths, that is nineteen twelfths. The tool goes through the product of the denominators, then reduces: the result always comes back in its simplest form.

Multiplying and dividing

Multiplication is the most direct: numerators together, denominators together. Division means multiplying by the reciprocal of the second fraction, in other words flipping it. Dividing by three quarters therefore amounts to multiplying by four thirds.

Reducing a fraction

Reducing means dividing numerator and denominator by their greatest common divisor. For twelve fifteenths that divisor is three, so the fraction becomes four fifths. The calculation runs on exact integers here, never through decimals: no rounding error can creep in.

What this tool does not do

This tool handles two fractions at a time, with integer numerators and denominators. It accepts no decimal input, chains no successive operations and manipulates no algebraic expressions.

Frequently asked questions

How do I enter a whole number?

Put it in the numerator and 1 in the denominator: the number 3 is written 3/1. For a mixed number such as two and a third, convert it to a fraction first, which gives 7/3.

Are negative fractions accepted?

Yes. The sign can sit on the numerator or the denominator, the result is the same. It is always moved to the numerator in the displayed answer.

Is my data sent to a server?

No: the text you type or paste is processed entirely in your browser, on your device. It is never transmitted to a server.

Do I need an account or an install?

No: the tool works directly on this page, with no sign-up and no installation.