Fraction Calculator
Add, subtract, multiply, or divide two fractions and get the simplified result plus its decimal value.
Last reviewed July 1, 2026
Working with fractions by hand means finding common denominators, keeping track of numerators, and simplifying at the end. This calculator does all of that instantly: pick an operation, enter two fractions, and get the answer reduced to its lowest terms, along with the decimal and percentage.
It handles addition, subtraction, multiplication, and division, and always simplifies the result so you get the cleanest possible fraction.
The Fraction formula
a/b + c/d = (ad + bc) ÷ bd; a/b − c/d = (ad − bc) ÷ bd; a/b × c/d = ac ÷ bd; a/b ÷ c/d = ad ÷ bca and c are the numerators (tops) · b and d are the denominators (bottoms). Every result is then reduced to lowest terms by dividing by the greatest common divisor.
Worked example
Add 1/2 and 1/3: (1×3 + 1×2) ÷ (2×3) = 5/6. As a decimal that's 5 ÷ 6 ≈ 0.833, or about 83.3%.
How to work with fractions
To add or subtract fractions you need a common denominator: multiply each fraction so both share the same bottom number, then add or subtract the tops. To multiply, multiply the tops and bottoms straight across. To divide, flip the second fraction and multiply.
Whatever the operation, the final step is simplifying — dividing the top and bottom by their greatest common divisor. This calculator does that automatically.
Frequently asked questions
▶How do I add two fractions?
Give them a common denominator, add the numerators, then simplify. For example 1/2 + 1/3 = 3/6 + 2/6 = 5/6. This calculator handles it for you.
▶How do I convert a fraction to a decimal?
Divide the numerator by the denominator — 3/4 = 3 ÷ 4 = 0.75. The calculator shows the decimal and percentage alongside the simplified fraction.
▶How do I multiply and divide fractions?
To multiply, multiply the numerators together and the denominators together: 2/3 × 3/4 = 6/12 = 1/2. To divide, flip the second fraction and multiply: 2/3 ÷ 3/4 = 2/3 × 4/3 = 8/9.
▶How do I simplify a fraction to lowest terms?
Divide the numerator and denominator by their greatest common divisor. For 8/12 the GCD is 4, so it simplifies to 2/3. This calculator simplifies every answer automatically.
▶How do I subtract fractions with different denominators?
Give them a common denominator, subtract the numerators, then simplify. For 3/4 − 1/6: rewrite as 9/12 − 2/12 = 7/12.
▶How do I turn a fraction into a percentage?
Convert it to a decimal by dividing top by bottom, then multiply by 100. So 3/4 = 0.75 = 75%. The calculator shows the percentage next to the decimal.
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Open calculator →Disclaimer: Fraction Calculator results are estimates for general information and education only, and are not financial, tax, legal or medical advice. Verify important decisions with a qualified professional.