Fraction Calculator
Enter two fractions or mixed numbers, pick an operation and get the exact answer as a simplified fraction, a mixed number and a decimal.
Last updated November 4, 2026
Use 0 for a plain fraction. Negative allowed.
Result
1 1/2 + 2 3/4 = 4 1/4
| Form | Value |
|---|---|
| Simplified fraction | 17/4 |
| Mixed number | 4 1/4 |
| Decimal | 4.25 |
Show the work
Formula: Convert each mixed number to an improper fraction, combine them, then divide top and bottom by their greatest common divisor.
- Improper fractions: 1 1/2 = 3/2 and 2 3/4 = 11/4.
- Combine: (3 × 4 + 11 × 2) / (2 × 4) = 34/8.
- Simplify: 34/8 = 17/4.
- Mixed number: 4 1/4. Decimal: 4.25.
Result: 1 1/2 + 2 3/4 = 17/4 = 4 1/4
How fractions are combined
a/b + c/d = (ad + bc) / bd
a/b × c/d = ac / bd
a/b ÷ c/d = ad / bc
A mixed number such as 2 1/3 is first turned into an improper fraction: multiply the whole part by the denominator, add the numerator, and keep the denominator. That gives 7/3.
Addition and subtraction use a common denominator, multiplication multiplies tops and bottoms, and division multiplies by the reciprocal of the second fraction. The result is then divided by the greatest common divisor of its top and bottom, so it is always in lowest terms.
All arithmetic uses exact integers, so 1/3 + 1/6 is exactly 1/2 and no rounding error creeps in. Only the decimal is rounded, to 8 places.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Negative numbers and limits
A negative whole part makes the whole mixed number negative, so -2 1/3 means -(2 + 1/3) = -7/3. For a negative proper fraction, enter 0 as the whole part and a negative numerator.
Denominators must be at least 1, and dividing by a fraction equal to zero is rejected. Each entry can be up to 1,000,000.
How to use the Fraction Calculator
- Enter the whole number, numerator and denominator of the first fraction (use 0 as the whole part for a plain fraction).
- Choose add, subtract, multiply or divide.
- Enter the second fraction in the same way.
- Read the simplified fraction, mixed number and decimal.
- Open Show the work for each step, or Copy, Print or Share the result.
Worked example
1 1/2 + 2 3/4: the improper fractions are 3/2 and 11/4. With a common denominator of 4 that is 6/4 + 11/4 = 17/4, which is 4 1/4 or 4.25.
| Operation | Fraction | Mixed number | Decimal |
|---|---|---|---|
| Add | 17/4 | 4 1/4 | 4.25 |
| Subtract | -5/4 | -1 1/4 | -1.25 |
| Multiply | 33/8 | 4 1/8 | 4.125 |
| Divide | 6/11 | 6/11 | 0.54545455 |
Frequently asked questions
How do I add fractions with different denominators?
Rewrite both over a common denominator, add the numerators, then simplify. For example, 1/2 + 1/3 = 3/6 + 2/6 = 5/6.
How do I enter a mixed number?
Type the whole part, then the numerator and denominator of the fraction part. For 2 1/3, enter 2, 1 and 3.
Why is my answer always in lowest terms?
The calculator divides the numerator and denominator by their greatest common divisor, so 6/12 is shown as 1/2.
What happens if I divide by zero?
Dividing by a fraction whose value is zero, or using a denominator of zero, is undefined, so the calculator shows an error message instead of a result.