Fraction Calculator

How to use the fraction calculator

Fraction arithmetic is the kind of thing that disappears from everyday use right up until you are halving a recipe or working out how much baseboard trim to buy. This calculator handles the four operations, reduces the result, and gives you a decimal and a mixed number alongside — so the answer is whichever form you need.

1. Enter each fraction as a numerator over a denominator. For mixed numbers like 2 1/3, convert to an improper fraction first (2 × 3 + 1 = 7, so 7/3).
2. Pick an operator: add, subtract, multiply, or divide.
3. The result appears simplified. For addition and subtraction the common denominator is computed for you (for 1/3 + 1/4 the intermediate is 4/12 + 3/12 = 7/12).

The formulas

• a/b + c/d = (a·d + b·c) / (b·d)
• a/b − c/d = (a·d − b·c) / (b·d)
• a/b × c/d = (a·c) / (b·d)
• a/b ÷ c/d = (a·d) / (b·c) — flip the second fraction and multiply

After any operation, divide the numerator and denominator by their greatest common divisor to reduce. That is the final form.