Fraction Calculator: Add, Subtract, Multiply and Divide Fractions

How to calculate with fractions?

An online fraction calculator quickly performs the four arithmetic operations on fractions: addition, subtraction, multiplication and division. It also simplifies fractions by reducing to the lowest common denominator using GCD, and converts fractions to decimal numbers and percentages.

Adding and subtracting fractions

To add or subtract two fractions, first find a common denominator (the LCM of both denominators). Multiply each numerator by the appropriate factor, then add or subtract the numerators. The result is then simplified by dividing by the GCD. Example: 1/2 + 1/3 = 3/6 + 2/6 = 5/6.

Multiplying and dividing fractions

Fraction multiplication is straightforward: multiply the numerators together and the denominators together, then simplify. Division becomes multiplication: a/b ÷ c/d = a/b × d/c (multiply by the reciprocal). Example: 2/3 × 3/4 = 6/12 = 1/2.

Simplifying a fraction

A fraction is irreducible when its numerator and denominator are coprime (GCD = 1). To simplify, divide both terms by their GCD. Example: 12/18 → GCD(12,18) = 6 → 12÷6 / 18÷6 = 2/3.