Fraction Calculator
Add, subtract, multiply and divide fractions with exact results. See the reduced answer plus mixed-number and decimal forms, with the working shown.
Enter fractions to see the result.
How to use
- 1
Enter the fractions
Type the numerators and denominators of two fractions and pick an operator.
- 2
Read the answer
The result appears as a reduced fraction, a mixed number and a decimal.
- 3
Or just simplify
Switch to the simplify mode to reduce a single fraction.
Features
- All four operations (+, −, ×, ÷)
- Results as reduced fraction, mixed number and decimal
- Working steps shown (common denominator, reduction)
- Exact integer arithmetic with no rounding error
Use cases
Checking homework
Verify fraction answers and see the working steps.
Scaling recipes
Work out amounts like "a third of a half cup" exactly.
DIY measurements
Add and subtract fractional measurements in inches.
Details
The fraction calculator performs exact arithmetic (addition, subtraction, multiplication and division) on two fractions. To avoid the rounding errors of floating-point math, it works entirely with integers: cross-multiplying numerators and denominators, then reducing with the greatest common divisor. 1/3 + 1/6 shows exactly 1/2, not 0.333…
For addition and subtraction the fractions are brought to a common denominator; multiplication multiplies across; division multiplies by the reciprocal. The result is reduced by the GCD, and when the numerator exceeds the denominator a mixed number is shown too. The working steps are displayed, so the tool doubles as a homework checker.
A zero denominator is rejected with an error, and non-integer input is also rejected. Everything runs in your browser and nothing you enter is transmitted.
FAQ
Is 1/3 + 1/6 shown exactly?
Yes. The calculation stays in integers, so the result is exactly 1/2.
Can the answer be shown as a mixed number?
Yes. When the answer is greater than one, a mixed number such as 1 2/3 is shown as well.
How do I simplify a single fraction?
Switch to the simplify mode to reduce one fraction and see its decimal form.
What happens if I enter zero as a denominator?
An error explains that zero is not allowed, because division by zero is undefined.
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All processing happens in your browser. Your files are never uploaded.
Verified: All four operations, reduction, mixed numbers, decimals and the zero-denominator error are covered by browser tests