Fraction Calculator
Add, subtract, multiply, or divide two fractions. Results are automatically simplified.
Simplify a fraction
About this tool
Fraction Calculator
Fraction Calculator adds, subtracts, multiplies and divides fractions, simplifies results, and converts between fractions and decimals.
How to use it
- Enter the numerator and denominator for each fraction.
- Choose the operation.
- Read the simplified result.
Why adding is the hard one
Multiplication and division of fractions are straightforward: multiply across, or invert the second and multiply. Neither needs a common denominator.
Addition and subtraction do. The fractions have to be rewritten over a shared denominator before the numerators can be combined, which is where most fraction errors happen. The result is then simplified by dividing both parts by their greatest common divisor.
Worked example
The default addition:
- Fractions1/2 + 1/2
- Common denominatoralready 2
Result: 2/2, which simplifies to 1.
When it helps
- Combining measurements in a recipe or a woodworking plan.
- Checking homework.
- Converting an awkward fraction to a decimal.
- Simplifying a fraction to its lowest terms.
Common mistakes
- Adding numerators and denominators separately. One half plus one half is one, not two quarters.
- Forgetting to simplify. 6/8 and 3/4 are the same value, but only one is the expected answer.
- Dividing by inverting the wrong fraction. It is the second one that flips.
