Fraction Calculator
Add, subtract, multiply and divide fractions and mixed numbers, with the working.
How to use Fraction Calculator
- Type the first fraction: 3/4, a mixed number such as 1 1/2 (with a space), a whole number or a decimal.
- Choose the operation and type the second fraction. Add a third if you need one.
- Read the simplified answer, its mixed-number and decimal forms, and the working.
How it works
Adding and subtracting: both fractions are rewritten over the least common denominator, then the tops are added or subtracted. Multiplying: tops are multiplied together and bottoms together. Dividing: the second fraction is flipped and multiplied. The answer is then simplified by dividing top and bottom by their greatest common divisor, found with Euclid’s algorithm.
Mixed numbers are converted to improper fractions first (1 1/2 = 3/2) and decimals to exact fractions (0.75 = 3/4). With three fractions, multiplication and division are done before addition and subtraction, the standard order of operations. All arithmetic uses exact whole numbers of any size, so there is no rounding error; only the decimal shown at the end is rounded, to 10 places.
Example
1/2 + 1/3: the common denominator is 6, so 3/6 + 2/6 = 5/6 (0.8333333333).
Frequently asked questions
How do I enter a mixed number?
Type the whole number, a space, then the fraction: 2 3/4. Negative mixed numbers work too: -1 1/2.
How do you add fractions with different denominators?
Find the least common denominator, rewrite each fraction over it, then add the tops. 1/4 + 1/6: the common denominator is 12, so 3/12 + 2/12 = 5/12.
How do you divide fractions?
Flip the second fraction and multiply. 1/2 ÷ 1/4 = 1/2 × 4/1 = 2.
Can it simplify a single fraction?
Yes. Enter the fraction and add 0: for example 18/24 + 0 gives 3/4.
Can I use decimals?
Yes. 0.75 is read as exactly 3/4, and you can mix decimals and fractions.
Limitations
- Up to three fractions per calculation.
- Repeating decimals are shown rounded to 10 places; the fraction itself is exact.
Last reviewed November 9, 2026. How we build and test tools.