Fraction calculator
Add, subtract, multiply or divide fractions, with steps.
11/12 = 0.916667
3/4 + 1/6 = 18/24 + 4/24 = 22/24
- Mixed numbers supported
- Shows the working steps
- Always simplified
How to calculate with fractions
- Enter each fraction, with a whole number if needed.
- Pick add, subtract, multiply or divide.
- Read the simplified answer, the steps and the decimal.
How to add and subtract fractions
Fractions only add or subtract directly when they count the same size pieces. Multiply the two denominators together to get a shared one, then scale each numerator by the other fraction's denominator before adding or subtracting.
Once both fractions sit over the same denominator, add or subtract the numerators and keep the denominator. Simplify the result to its lowest terms at the end.
| Problem | Common denominator | Answer |
|---|---|---|
| 2/3 + 1/4 | 12: 8/12 + 3/12 | 11/12 |
| 5/6 - 1/3 | 18: 15/18 - 6/18 | 1/2 |
| 1 1/2 + 2 1/3 | 6: 9/6 + 14/6 | 3 5/6 |
Multiplying and dividing fractions
- Multiplying skips the common denominator step. Multiply the numerators together and the denominators together: 2/3 x 3/4 = 6/12, which simplifies to 1/2.
- Dividing flips the second fraction and multiplies: 3/4 divided by 2/5 becomes 3/4 x 5/2 = 15/8, or 1 and 7/8 as a mixed number.
Common fraction mistakes
- Adding numerators and denominators straight across. 1/2 + 1/3 is not 2/5. It needs a common denominator first: 3/6 + 2/6 = 5/6, the correct answer.
- Forgetting to flip the second fraction when dividing. 1/2 divided by 1/4 is not 1/2 x 1/4, which gives 1/8. Flip the second fraction first: 1/2 x 4/1 = 4/2 = 2.
- Forgetting to simplify. A correct but unsimplified answer like 6/8 should still be reduced to 3/4 before you use it.
Fraction to decimal quick reference
Fractions stay exact for values that decimals can only approximate, like thirds (1/3 is 0.333 repeating forever) or the eighths and sixteenths of an inch used on a tape measure and in woodworking plans. Decimals are usually easier for money, metric measurements and anything you plan to type into another calculator, since they do not need simplifying or a common denominator first.
These common conversions are worth knowing for a quick mental check on any result.
| Fraction | Decimal |
|---|---|
| 1/2 | 0.5 |
| 1/3 | 0.333 |
| 1/4 | 0.25 |
| 1/8 | 0.125 |
| 1/16 | 0.0625 |
| 3/4 | 0.75 |
| 2/3 | 0.667 |
Fraction calculator FAQ
What is 3/4 plus 1/6?
3/4 + 1/6 = 11/12. The common denominator is 24, giving 18/24 + 4/24 = 22/24, which simplifies to 11/12.
How do mixed numbers work?
Enter the whole number and the fraction part separately, like 1 and 1/2 for one and a half. The sign goes on the whole number for a negative mixed number.
Is the answer always simplified?
Yes. Every result is reduced to its lowest terms automatically.
What happens if I divide by zero?
You get an error message instead of a result, since dividing by zero is undefined.
Does this work for very large numbers?
Yes. The math uses arbitrary-precision integers internally, so large numerators and denominators do not lose precision.
How do I turn a fraction into a decimal?
Divide the numerator by the denominator. 5/8 works out to 0.625, and this tool shows that decimal automatically under the result.
How do I simplify a fraction by hand?
Divide the numerator and denominator by their greatest common factor. For 8/12, that factor is 4, which reduces it to 2/3, the same answer this tool gives instantly.
Why does the denominator matter when adding fractions?
The denominator sets the size of each piece. 1/3 and 1/4 cannot be added directly because thirds and quarters are different sizes, so both get rewritten over a shared denominator first.