Fraction Calculator

Add, subtract, multiply or divide two fractions or mixed numbers and see the simplified answer as a fraction, a mixed number and a decimal — with every step shown.

🔒 Runs entirely in your browser — nothing is sent anywhere

Your fractions

First fraction
Second fraction

Leave the whole box blank for a simple fraction, or fill it in for a mixed number like 2 1/3. Leave a denominator blank to treat it as 1.

How this works

Every fraction is handled with exact whole-number arithmetic, so there are no rounding errors — and the answer is always fully simplified.

1

Make them improper

Any mixed number, like 2 1/3, is turned into a single improper fraction (7/3) so both inputs are in the same shape.

2

Apply the operation

Add, subtract, multiply or divide using integer maths. For + and − we put both fractions over a common denominator first.

3

Simplify the answer

We divide the top and bottom by their greatest common divisor, then show the result as a fraction, a mixed number and a decimal.

The formulas we use

Add & subtract

a⁄b ± c⁄d = (a·d ± c·b) ⁄ (b·d)

Both fractions are rewritten over the common denominator b·d, then the numerators are combined and the answer is simplified.

Multiply & divide

a⁄b × c⁄d = (a·c) ⁄ (b·d)

a⁄b ÷ c⁄d = (a·d) ⁄ (b·c)

Dividing flips the second fraction and multiplies. Division is undefined if the second fraction is zero.

A denominator can never be zero — that is undefined in mathematics — so the calculator flags it instead of guessing. Negative fractions are fully supported: enter the minus sign on the whole number or the numerator.

🔒

Private by design. Every number stays on your device. Nothing you type is uploaded, stored or shared.

Frequently Asked Questions

How does this fraction calculator work? ▼
Enter two fractions — each with an optional whole number for mixed numbers — and pick an operation (+, −, ×, ÷). The tool converts each mixed number to an improper fraction, applies the operation with exact integer arithmetic, then simplifies the answer by dividing the top and bottom by their greatest common divisor (GCD). It shows the result as an improper fraction, a mixed number and a decimal.
What is a mixed number and how do I enter one? ▼
A mixed number combines a whole number and a proper fraction, like 2 1/3 (two and one-third). Type the whole part in the first box and the fraction in the numerator and denominator boxes. The calculator converts 2 1/3 to the improper fraction 7/3 before doing the maths. For a negative mixed number such as −2 1/3, enter −2 as the whole number.
How are fractions simplified? ▼
A fraction is in its simplest form when the numerator and denominator share no common factor other than 1. The calculator finds the greatest common divisor of the top and bottom numbers using Euclid's algorithm, then divides both by it. For example, 6/8 has a GCD of 2, so it simplifies to 3/4.
How do you add or subtract fractions with different denominators? ▼
You first rewrite both fractions over a common denominator — this tool uses the product of the two denominators — then add or subtract the numerators. For a/b ± c/d the result is (a·d ± c·b) / (b·d), which is then simplified. For example, 1/2 + 1/3 = (3 + 2) / 6 = 5/6.
What happens if a denominator is zero? ▼
A denominator of zero is undefined in mathematics, so the calculator flags it and will not compute a result. Dividing by a fraction that equals zero is also undefined — you cannot divide by zero — so the tool shows a clear error in that case too.
Is my data private? ▼
Yes. Every calculation runs entirely in your browser using plain JavaScript. Nothing you type is uploaded, stored or shared, and the tool works even with no network connection.

Free to use · works entirely in your browser · no account needed.

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