How to use Fraction Calculator
- Choose an operation in What do you want to do?
- Enter each value as a whole number, a fraction like 3/4, or a mixed number like 1 1/2.
- Set Decimal places. The answer updates as you change the values.
- Read the equation, the reduced fraction, the mixed form and the decimal.
Example: Fraction Calculator
Add two fractions with different denominators.
Options
- What do you want to do?
- The five choices are add, subtract, multiply, divide and simplify. The input labels change with the operation, so divide asks for a Dividend and a Divisor.
- Mixed number input
- Write a mixed number with a space, such as 1 1/2. A minus sign in front applies to the whole value, so -1 1/2 is -3/2, and a sign inside the fraction part is rejected.
Supported inputs and limits
Where your input is processed
This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.
Which fractions end in an exact decimal
Look at the denominator after the fraction is reduced. If only twos and fives divide it, the decimal stops: 1/2 is 0.5, 1/5 is 0.2, 3/8 is 0.375. Any other prime makes it repeat forever, so 1/3 and 1/7 never finish.
Why the answer stays exact until the decimal line
Each value is a numerator and denominator pair reduced by their greatest common divisor, so no stage is stored as a rounded float. Adding 1/3 and 1/6 gives exactly 1/2. Only the decimal line rounds, and only as far as you asked.
Questions about Fraction Calculator
Why does it tell me to write 0.5 as 1/2?
Input stays exact, and a typed decimal can hide how many places you meant. The decimal answer still appears on the result line.
How is a negative mixed number read?
The sign in front applies to the whole quantity, so -1 1/2 means -3/2. Write the sign once, in front.
Why does the decimal say rounded rather than exact?
A fraction has a terminating decimal only when its denominator is built from twos and fives. One third repeats forever, so the decimal is shown to your chosen places.
What happens if I divide by zero?
The calculation is refused, because dividing by zero has no answer. You get an error naming the second value.