How do you add two fractions?

First give them the same bottom number. Then add the top numbers and reduce the answer if possible. For example, 1/2 + 1/3 = 3/6 + 2/6 = 5/6.

How do you divide fractions?

Flip the second fraction, then multiply. So dividing by 2/3 is the same as multiplying by 3/2.

What does 'simplified' mean?

The top and bottom numbers have been divided by the largest number that goes into both. So 6/8 becomes 3/4.

What is a mixed number?

It is a whole number plus a fraction smaller than 1. For example, the improper fraction 7/3 can be written as 2 1/3.

Can the result be negative?

Yes. Enter a negative top number, or subtract a larger fraction from a smaller one.

Can I share a calculation?

Yes. Select Share to copy a link that opens the calculator with the same fractions and operation.

Fraction calculator

Enter two fractions and choose what to do with them. You get the answer in its simplest form, plus a decimal and a mixed number where that helps.

Written by Kenneth Schrøder, Founder of WiseCalcs

Updated September 9, 2026·Sources verified September 8, 2026

Use this fraction calculator to add, subtract, multiply, or divide two fractions. It lets you compare the exact answer with a decimal and a mixed number.

Result

5/6

Decimal: 0.8333
Mixed number: 5/6

The answer changes as you type. The simplified fraction is exact for accepted inputs. The decimal has up to four places and is rounded if needed. A mixed number can make an improper fraction easier to read.

How does it work?

To add or subtract, first make the bottom numbers the same. To multiply, multiply top by top and bottom by bottom. To divide, turn the second fraction upside down and multiply. The answer is reduced by dividing the top and bottom numbers by the same number.

How fraction calculations work

\frac{a}{b} \pm \frac{c}{d} = \frac{ad \pm cb}{bd},\quad \frac{a}{b}\times\frac{c}{d}=\frac{ac}{bd}

a, c: The top numbers, also called numerators, in the two fractions.
b, d: The bottom numbers, also called denominators, in the two fractions.

1/2 + 1/3 = (1×3 + 1×2) / (2×3) = 5/6 ≈ 0.8333. To divide, turn the second fraction upside down, then multiply.

Method & sources

Numerators must be whole numbers, and denominators must be positive whole numbers. For addition and subtraction, the calculator uses a common denominator. For multiplication, it multiplies top numbers together and bottom numbers together. For division, it flips the second fraction and multiplies. It reduces the answer as far as possible by dividing the numerator and denominator by the largest number that fits into both.

Sources

Where this method comes from — use these references to understand the formula, assumptions, and limits.

Fractions — key concepts and operations — OpenStax, Rice University, verified 2026-09-08

How we calculate

Numerators must be whole numbers, and denominators must be positive whole numbers.
For addition and subtraction, the calculator uses a common denominator. For multiplication, it multiplies top numbers together and bottom numbers together. For division, it flips the second fraction and multiplies.
It reduces the answer as far as possible by dividing the numerator and denominator by the largest number that fits into both.
You cannot divide by a fraction equal to zero.

Rounding

For accepted inputs, the fraction answer is exact. The decimal display has up to four decimal places and is rounded when needed. At an exact halfway point, it rounds toward +∞, so −1.23445 is shown as −1.2344.

What this calculator does

For addition and subtraction, the fractions need the same bottom number, called a common denominator. For multiplication, multiply the top numbers together and the bottom numbers together. For division, flip the second fraction and multiply. The calculator then reduces the answer if it can.

How to use it

Enter the top and bottom number of the first fraction.
Choose add, subtract, multiply, or divide.
Enter the top and bottom number of the second fraction.
Read the simplified fraction, decimal, and mixed number.

A worked example

For 1/2 + 1/3, use 6 as the common denominator. That gives 3/6 + 2/6 = 5/6. The decimal is 0.8333, and 5/6 stays the same because it cannot be reduced further.

Reducing and mixed numbers

The calculator reduces the answer by dividing the top and bottom numbers by the largest number that goes into both. So 4/8 becomes 1/2. When the top number is bigger than the bottom one, a mixed number may be easier to read: 7/3 = 2 1/3.

Exact fraction or decimal?

The simplified fraction keeps the exact value. The decimal shows up to four places and is rounded if needed. For example, 1/2 is 0.5, while 1/3 is shown as 0.3333. Keep the fraction when you need to calculate further or need an exact ratio. Use the decimal for an estimate or a quick comparison.

A practical recipe-scaling example

Suppose a recipe needs 3/4 cup, but you are making 2/3 of it. Multiply 3/4 by 2/3. The first answer is 6/12, which reduces to 1/2 cup. Here, 1/2 is often more useful than 0.5 because measuring cups use fractions.

Subtraction, division, and zero

In 1/4 − 3/4, both fractions already have 4 at the bottom. The answer is −2/4 = −1/2.
For 2/3 ÷ 4/5, flip 4/5 to 5/4, then multiply: 2/3 × 5/4 = 10/12 = 5/6.
A top number of zero is fine: it means 0. A bottom number of zero has no value. You also cannot divide by a zero fraction such as 0/5.

Use the percentage calculator to see the answer as a percentage. Use the rounding calculator for a rounded decimal, or the basic calculator when you no longer need an exact fraction.

Common mistakes

Adding the top numbers and bottom numbers straight across instead of finding a common denominator first.
Using zero as the bottom number, which is not allowed.
Forgetting to flip the second fraction before dividing.

When it's useful

Use it for homework, cooking, changing recipe amounts, measurements, or any task where an exact fraction is better than a rounded decimal.

FAQ

How do you add two fractions?: First give them the same bottom number. Then add the top numbers and reduce the answer if possible. For example, 1/2 + 1/3 = 3/6 + 2/6 = 5/6.
How do you divide fractions?: Flip the second fraction, then multiply. So dividing by 2/3 is the same as multiplying by 3/2.
What does 'simplified' mean?: The top and bottom numbers have been divided by the largest number that goes into both. So 6/8 becomes 3/4.
What is a mixed number?: It is a whole number plus a fraction smaller than 1. For example, the improper fraction 7/3 can be written as 2 1/3.
Can the result be negative?: Yes. Enter a negative top number, or subtract a larger fraction from a smaller one.
Can I share a calculation?: Yes. Select Share to copy a link that opens the calculator with the same fractions and operation.

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