Fraction Calculator

The Fraction Calculator adds, subtracts, multiplies, and divides any two fractions and returns the result fully simplified, along with its decimal equivalent. It handles the classic homework problems - unlike denominators, borrowing across wholes, and reducing to lowest terms - and it is equally useful for practical measurements such as woodworking plans and recipe scaling.

For addition and subtraction the tool cross-multiplies over the common denominator: a/b + c/d becomes (ad + cb)/bd. Multiplication multiplies the numerators and denominators directly, and division multiplies by the reciprocal, turning a/b divided by c/d into a x d over b x c. Every result is then reduced using the greatest common divisor, so 4/8 comes back as 1/2 rather than an unsimplified intermediate.

A few usage notes: denominators cannot be zero, and a negative sign belongs on the numerator for cleanest output. Division by a fraction with a zero numerator will produce an error because division by zero is undefined. If you need to convert the decimal equivalent back into a fraction or work with mixed numbers, split the whole part first and enter the remainder here.

Everything is computed locally in your browser using exact integer arithmetic, so there is no floating-point drift in the fraction result.