Fraction calculator — add, subtract, multiply, divide
Add, subtract, multiply and divide fractions with exact results — automatically simplified, with the mixed number and decimal shown alongside.
Runs entirely in your browser — nothing is uploaded.
Decimal to fraction
Results are exact rational arithmetic, simplified by the greatest common divisor. The decimal is shown for convenience and may be rounded.
How to use
- Enter both fractions. Numerator on top, denominator below.
- Pick an operation. Plus, minus, times or divide.
- Read the result three ways. Simplified fraction, mixed number, and decimal.
- Or convert a decimal. The panel below turns any decimal into its exact fraction.
Questions
How do I add fractions with different denominators?
Cross-multiply to get a common denominator: a/b + c/d = (ad + cb) / bd. So 1/2 + 1/3 = (3 + 2)/6 = 5/6. The tool then divides through by the greatest common divisor to simplify.
How does dividing fractions work?
Multiply by the reciprocal — flip the second fraction and multiply. 1/2 ÷ 1/4 becomes 1/2 × 4/1 = 4/2 = 2.
How does 0.333333 become exactly 1/3?
A continued-fraction search finds the simplest fraction matching the digits you gave. That returns 1/3 rather than 333333/1000000, which is almost always what you meant.
What is a mixed number?
A whole part plus a proper fraction — 5/2 written as 2½. It is shown whenever the result is larger than one.