Fraction Calculator
Add, subtract, multiply or divide fractions, simplified automatically.
Denominators cannot be zero. Negative numerators are allowed for negative fractions.
Working with fractions
Multiplying fractions is direct — multiply the tops, multiply the bottoms. Dividing flips the second fraction and multiplies. Adding and subtracting need a common denominator first, so the parts are the same size before you combine them.
| Add / subtract | a/b ± c/d = (ad ± cb) / bd |
|---|---|
| Multiply | a/b × c/d = ac / bd |
| Divide | a/b ÷ c/d = ad / bc |
Whatever the operation, the answer is then reduced to lowest terms by dividing the top and bottom by their greatest common divisor.
One half plus one third is found over a common denominator of 6: 3/6 + 2/6 = 5/6. That is already in lowest terms — about 0.833 as a decimal, or 83.33%.
Three ways to read the same value
A fraction, a decimal and a percentage are three views of one number. Fractions are exact and great for reasoning; decimals are easy to compare and feed into other sums; percentages communicate proportion at a glance. Seeing all three together helps the idea click.
Tips that help
- Simplify early. Smaller numbers are easier to work with and to check.
- Common denominators only for + and −. Multiplying and dividing do not need them.
- Improper is fine. 7/4 and 1 3/4 are the same value — use whichever is clearer.