Fraction Calculator
Add, subtract, multiply, or divide two fractions — with the answer simplified to lowest terms and shown as a decimal.
How fraction operations work
Multiply: (a/b) × (c/d) = ac/bd
Divide: (a/b) ÷ (c/d) = (a/b) × (d/c)
Simplify: divide top and bottom by their GCD
1/2 + 1/3: common denominator 6 → 3/6 + 2/6 = 5/6 ≈ 0.833.
Fractions in practice
Fractions show up in recipes, measurements, and woodworking far more than decimals do. The two rules that matter: you can only add or subtract fractions once they share a denominator, and you should always simplify the answer (8/12 and 2/3 are the same number, but 2/3 is the accepted form). To turn a fraction into a percentage, divide and multiply by 100 — the percentage calculator does the rest. For ratios and scaling, see the ratio calculator.
Frequently asked questions
How do you add fractions?
Common denominator, add numerators, simplify. 1/2 + 1/3 = 5/6.
How do you multiply and divide fractions?
Multiply straight across; to divide, flip the second and multiply.
How do you simplify a fraction?
Divide top and bottom by their greatest common divisor. 8/12 → 2/3.
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Last reviewed: July 2026.