Fraction Calculator

Written byOleh Soloninupdated 5 October 2026

Whole part A

For a mixed number such as 2 in 2 1/3; leave 0 for a plain fraction.

A Numerator

A Denominator

Operator

Whole part B

B Numerator

B Denominator

Result

Fraction Result5/6
Working1/2 + 1/3 = 3/6 + 2/6 = 5/6
Decimal Result0.833333

Four operations, answers already simplified

Do arithmetic with fractions and get the answer in lowest terms. Shows the working method so it is useful for checking homework.

Fraction arithmetic is where the rules stop being intuitive. Adding needs a common denominator; multiplying does not. Dividing means flipping the second fraction and multiplying.

Enter both fractions and the operation, and the result comes back reduced — 6/8 is shown as 3/4, because that is the form a teacher or a recipe expects.

How to use

Enter the first fraction: whole part, numerator and denominator.
Choose the operation and enter the second fraction.
Read the result as a fraction, as a mixed number and as a decimal, with the working shown.

Common denominators and the rule for division

Adding and subtracting needs a common denominator: 1/2 + 1/3 becomes 3/6 + 2/6 = 5/6. The denominator to reach for is the least common multiple of the two, which keeps the numbers small and the answer close to lowest terms.

Multiplication needs nothing at all — numerators and denominators pair off. Division inverts the second fraction and multiplies: 3/4 ÷ 2/5 is 3/4 × 5/2 = 15/8, or 1 and 7/8.

Worked out with this calculator; results are reduced to lowest terms.
Expression	Working	Result
1/2 + 1/3	3/6 + 2/6	5/6
3/4 − 1/6	9/12 − 2/12	7/12
3/4 × 2/5	6/20	3/10
3/4 ÷ 2/5	3/4 × 5/2	15/8

What this calculator shows

The result of the operation, reduced to lowest terms
Addition, subtraction, multiplication and division
A simplified answer rather than an unwieldy raw fraction

What to keep in mind

Denominators cannot be zero; the tool will not accept it.
Results come as a fraction in lowest terms, and an improper one is also shown as a mixed number: 7/4 = 1 3/4.

FAQs

Why do I need a common denominator to add but not to multiply?

Adding combines parts, so the parts must be the same size first. Multiplying scales one fraction by another, and the sizes take care of themselves.

How do I divide by a fraction?

Flip the second fraction and multiply. 1/2 ÷ 1/4 becomes 1/2 × 4/1 = 2 — there are indeed two quarters in a half.

What is an improper fraction?

One where the top is at least as big as the bottom, like 7/4 or 4/4. It is perfectly valid and often easier to keep calculating with than the mixed form.

Does it always simplify?

Yes. The result is divided by the greatest common divisor of both parts, so 10/20 comes back as 1/2.

How do I add 1/2 and 1/3?

Rewrite both over 6: 3/6 + 2/6 = 5/6. The common denominator is the least common multiple of the two denominators.

How do I divide one fraction by another?

Invert the second and multiply. 3/4 ÷ 2/5 is 3/4 × 5/2 = 15/8, which is 1 and 7/8. Mixed numbers must be rewritten as improper fractions first.

Worked example

Two thirds plus a quarter

Input: 2/3 + 1/4

Output: 11/12

Note: Twelve is the smallest number both 3 and 4 divide into, giving 8/12 + 3/12. Close to 1 but not quite there.

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Fraction Calculator

Result

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