Fraction Calculator
Add, subtract, multiply and divide fractions and mixed numbers with exact integer math — results are reduced to lowest terms and shown as an improper fraction, a mixed number and a decimal. You can also simplify a single fraction or convert a decimal to a fraction. Everything runs in your browser.
Leave the small whole-number box empty for a plain fraction, or fill it for a mixed number like 2 3/4.
Enter any fraction and it is reduced to lowest terms using the GCD.
The decimal is read exactly from the digits you type and reduced to its simplest fraction.
- Improper fraction
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- Mixed number
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- Decimal
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How to use the fraction calculator
- Pick a mode: Calculate two fractions, Simplify one fraction, or Decimal ↔ Fraction.
- Type the numerator and denominator. Add a whole number for a mixed number such as
2 3/4. - Choose
+,−,×or÷. Results update live and appear reduced to lowest terms.
Every answer is given three ways: an improper fraction (like 11/4), a mixed number (2 3/4)
and a decimal (2.75). All arithmetic uses whole-number integer math, so results are exact rather than rounded.
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Frequently asked questions
How does the fraction calculator work?
Enter two fractions — each with a numerator and denominator, plus an optional whole-number part for mixed numbers — and pick an operation (+, −, ×, ÷). The result is computed with exact integer math, reduced to lowest terms, and shown as an improper fraction, a mixed number and a decimal.
How are fractions reduced to lowest terms?
The calculator divides the numerator and denominator by their greatest common divisor (GCD), found with the Euclidean algorithm. For example 8/12 has a GCD of 4, so it reduces to 2/3. The sign is always carried on the numerator and a zero result is shown as 0.
What is a mixed number?
A mixed number combines a whole number with a proper fraction, such as 2 3/4, which equals the improper fraction 11/4. Type the whole part in the first box of each fraction; a negative whole part makes the whole fraction negative.
What happens if I divide by zero?
Division is undefined when a denominator is 0 or when you divide by a fraction that equals zero. The calculator detects both cases and shows a clear error instead of a result, so you never get a misleading answer.
How do I convert a decimal to a fraction?
Use the Decimal ↔ Fraction mode and type a decimal such as 0.375. It is read as 375/1000 and reduced to its simplest form 3/8. Repeating decimals are approximated from the digits you enter, not detected automatically.
Is my data sent anywhere?
No. Every calculation runs entirely in your browser with plain integer arithmetic — nothing is uploaded to a server and nothing is stored.