Fraction Calculator
The fraction calculator adds, subtracts, multiplies, and divides fractions or simplifies a single value. It accepts common fractions such as 3/4, mixed numbers such as 1 1/2, integers, and decimals.
Every answer is reduced to lowest terms and also displayed as a mixed number, decimal, and percentage. The working line shows the formula with the entered values substituted.
Simplification examples
Reduced result
13/6
Working: 3/2 + 2/3 = (3 × 3 + 2 × 2) ÷ (2 × 3) = 13/6
Mixed number
2 1/6
Decimal
2.1666666667
Percentage
216.66666667%
Entering fractions, mixed numbers, and decimals
- Type a common fraction with a slash, such as 7/12. Its denominator cannot be zero.
- Put a space between the whole and fractional parts of a mixed number: 2 3/5 means two and three fifths.
- Decimals such as 0.75 are converted to an exact fraction before the operation begins.
- Place a minus sign before the entire value for a negative fraction or mixed number: -3/4 or -1 1/2.
Adding and subtracting fractions
When denominators match, add or subtract only the numerators. For example, 3/8 + 2/8 = 5/8. The denominator describes the size of each part and remains eight.
Different denominators need a common denominator. Addition follows a/b + c/d = (a × d + c × b) / (b × d). Thus 1/2 + 2/3 = (1 × 3 + 2 × 2) / 6 = 7/6 = 1 1/6. Subtraction uses the same formula with a minus sign in the numerator.
Multiplying and dividing fractions
To multiply fractions, multiply across: a/b × c/d = (a × c) / (b × d). For example, 2/3 × 9/10 = 18/30 = 3/5. Common factors may be canceled before or after multiplication without changing the exact result.
Division means multiplying by the reciprocal of the second fraction: a/b ÷ c/d = a/b × d/c. For example, 3/4 ÷ 2/5 = 3/4 × 5/2 = 15/8 = 1 7/8. Division by a zero fraction is undefined.
Simplifying fractions and making mixed numbers
Reduce a fraction by dividing its numerator and denominator by their greatest common divisor. The GCD of 18 and 60 is 6, so 18/60 becomes 3/10. Likewise, 18/24 reduces to 3/4. The calculator always returns the final fraction in lowest terms.
An improper fraction has a numerator at least as large as its denominator. Divide the numerator by the denominator to make a mixed number: the quotient is the whole part and the remainder is the new numerator. For example, 13/6 = 2 1/6.
Common fractions as decimals and percentages
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/8 | 0.125 | 12.5% |
| 1/5 | 0.2 | 20% |
| 1/4 | 0.25 | 25% |
| 1/3 | 0.333… | 33.333…% |
| 1/2 | 0.5 | 50% |
| 2/3 | 0.666… | 66.666…% |
| 3/4 | 0.75 | 75% |
Why some decimal answers repeat
A reduced fraction terminates as a decimal only when its denominator contains no prime factors other than 2 and 5. That is why 3/8 equals exactly 0.375, while 1/3 produces the repeating decimal 0.333….
The calculator keeps the arithmetic as an exact ratio of integers. The decimal display may be rounded, but the reduced common fraction remains exact.
Frequently asked questions
How do I add fractions with different denominators?
Use a common denominator, add the adjusted numerators, and reduce. The direct formula is a/b + c/d = (a × d + c × b) / (b × d).
How do I divide one fraction by another?
Flip the second fraction and multiply: a/b ÷ c/d = a/b × d/c. The second fraction must be nonzero.
How do I simplify a fraction?
Find the greatest common divisor of the numerator and denominator and divide both by it. For example, 18/24 reduces to 3/4.
Can 18/60 be simplified?
Yes. The greatest common divisor of 18 and 60 is 6. Divide both by 6 to get 18/60 = 3/10.
How do I turn a mixed number into an improper fraction?
Multiply the whole part by the denominator, add the numerator, and put that total over the original denominator: 2 1/3 = (2 × 3 + 1) / 3 = 7/3.
How do I convert a fraction to a percentage?
Divide the numerator by the denominator and multiply by 100%. For example, 3/5 = 0.6 = 60%.
Can this calculator handle negative fractions?
Yes. Put the minus sign before the fraction or mixed number, such as -3/4 or -1 1/2. The ordinary sign rules then apply.
Updated: 2026-08-16