➗ Fraction Calculator
Add, subtract, multiply or divide two fractions or mixed numbers and see the simplified answer with step-by-step working.
Quick answer: To add fractions, rewrite them over a common denominator and add the numerators: 1/2 + 3/4 = 2/4 + 3/4 = 5/4, which is the mixed number 1 1/4 or 1.25 as a decimal.
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Fraction Calculator inputs
Result
1/2 + 3/4 =
5/4
Mixed number: 1 1/4
- Simplified fraction
- 5/4
- Mixed number
- 1 1/4
- Decimal
- 1.25
- Percent
- 125%
Step by step
- Lowest common denominator of 2 and 4 is 4: 1/2 = 2/4, 3/4 = 3/4
- Add the numerators: 2/4 + 3/4 = 5/4
- 5/4 is already in simplest form
- As a mixed number: 1 1/4
- As a decimal: 5/4 = 1.25
How fraction arithmetic works
Every fraction has a numerator (the top number, how many parts you have) and a denominator (the bottom number, how many equal parts make a whole). The four operations follow simple rules:
a/b + c/d = (ad + bc) / bd · a/b × c/d = ac / bd · a/b ÷ c/d = a/b × d/c
- Adding and subtracting: the denominators must match. Find the lowest common denominator (LCD), convert each fraction, then add or subtract only the numerators.
- Multiplying: multiply the numerators together and the denominators together – no common denominator needed.
- Dividing: flip the second fraction upside down and multiply.
Finally, simplify by dividing the numerator and denominator by their greatest common divisor (GCD).
Worked example
1/2 + 3/4: the LCD of 2 and 4 is 4, so 1/2 becomes 2/4. Then 2/4 + 3/4 = 5/4. Because the numerator is bigger than the denominator, it is an improper fraction – as a mixed number it is 1 1/4, and as a decimal 1.25.
Working with mixed numbers
Convert a mixed number to an improper fraction before calculating: multiply the whole number by the denominator and add the numerator. So 2 3/8 = (2 × 8 + 3)/8 = 19/8. The calculator does this for you and converts the answer back.
| Fraction | Decimal | Percent |
|---|---|---|
| 1/8 | 0.125 | 12.5% |
| 1/4 | 0.25 | 25% |
| 1/3 | 0.333… | 33.33% |
| 1/2 | 0.5 | 50% |
| 2/3 | 0.666… | 66.67% |
| 3/4 | 0.75 | 75% |
Tips
- When multiplying, cancel common factors diagonally first to keep the numbers small.
- A negative sign can go on the numerator, the denominator or in front – they all mean the same thing.
- Check your answer by converting everything to decimals: 0.5 + 0.75 = 1.25.
Frequently asked questions
How do I enter a mixed number?
Type the whole number, a space, then the fraction – for example 2 3/8. Negative mixed numbers work too: -1 1/2 means minus one and a half. You can also type whole numbers (5) or decimals (0.75).
How do you divide fractions?
Keep the first fraction, flip the second one (take its reciprocal) and multiply. For example 2/3 ÷ 4/5 = 2/3 × 5/4 = 10/12, which simplifies to 5/6.
What does “simplest form” mean?
A fraction is in simplest form when the numerator and denominator share no common factor other than 1. Divide both by their greatest common divisor to get there – 18/24 becomes 3/4 after dividing by 6.
How do I turn a fraction into a decimal?
Divide the numerator by the denominator. 5/8 = 5 ÷ 8 = 0.625. Some fractions, like 1/3, give a repeating decimal (0.333…), which the calculator rounds to 10 decimal places.