Fraction Calculator
Type fractions naturally and see an exact answer, mixed number, decimal, and the working immediately — no button needed.
- Runs in your browser — files never leave your device
- Fewer clicks, keyboard friendly
- More accurate results
Exact fraction arithmetic updates as you type — no calculate button needed.
Saved in this browserOperation
Answer
… means the decimal continues
Working
- Use the least common denominator 6: 3/6 + 2/6
- 3/6 + 2/6 = 5/6
- 5/6 is already in simplest form
Calculated exactly in your browser. Your inputs are saved only on this device and are never sent to a server.
How to use
- Type the first value as a fraction such as 3/4, a mixed number such as 1 2/3, an integer, or a finite decimal.
- Choose add, subtract, multiply, or divide.
- Type the second value in the same format.
- Read the simplified fraction, mixed-number form, decimal form, and operation-specific working as they update.
- Use Copy answer to paste the exact result and working into your notes.
Why addition and subtraction need a common denominator
Fractions can be added or subtracted only after their parts have the same size. This calculator uses the least common denominator (LCD), the least common multiple of the two denominators, rather than simply multiplying them. For 1/6 + 1/4, the LCD is 12: 1/6 becomes 2/12 and 1/4 becomes 3/12, so the answer is 5/12. Using 24 would still work, but it creates 4/24 + 6/24 and requires an extra reduction step.
Multiplication, division, and exact results
To multiply fractions, multiply numerators together and denominators together, then reduce the result. To divide by a fraction, multiply by its reciprocal: 5/6 ÷ 2/3 becomes 5/6 × 3/2 = 15/12 = 5/4. The calculation stays as whole-number numerator and denominator arithmetic throughout, so values such as 1/3 are never rounded to an inexact decimal before calculating. Dividing by 0 has no mathematical result, including dividing by a fraction whose numerator is 0.
Fractions, mixed numbers, and decimals
An improper fraction and a mixed number express the same value: 13/6 is 2 1/6 because 13 ÷ 6 leaves a remainder of 1. A terminating decimal can be converted exactly: 0.125 = 125/1000 = 1/8. Some fractions do not terminate as decimals; 1/3 is 0.333… because the remainder repeats. This tool shows up to 12 decimal digits and adds an ellipsis when more digits continue, while the displayed fraction remains exact.
Frequently asked questions
How do I enter a mixed number?
Enter a mixed number with a space between the whole number and fraction, such as 2 3/4. A leading minus sign applies to the entire mixed number, so -2 3/4 means negative 11/4, not negative 5/4.
How do you add fractions with different denominators?
Find a common denominator, rewrite both fractions with that denominator, and then add the numerators. For example, 1/2 + 1/3 becomes 3/6 + 2/6 = 5/6. This calculator uses the least common denominator and shows the rewritten fractions in the working.
Why does dividing by a fraction mean multiplying by its reciprocal?
Dividing by a fraction asks how many of that fraction fit into a value, which is equivalent to multiplying by the fraction turned upside down. For example, 5/6 ÷ 2/3 = 5/6 × 3/2 = 5/4.
Can this calculator use decimals?
Yes. Finite decimals such as 0.125 are converted exactly to fractions before calculation, so 0.125 is treated as 1/8 rather than as a rounded approximation. Repeating-decimal notation such as 0.(3) is not an input format.
Are my fraction calculations sent to a server?
No. Every calculation is performed locally in your browser using exact integer arithmetic. Inputs are saved only in this browser so they remain after refresh, and they are never sent to a server.
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Updated 2026-10-13