How to use it
- Enter the numerator and denominator of the first fraction (Fraction A).
- Pick an operation from the middle drop-down: add (+), subtract (−), multiply (×) or divide (÷).
- Enter the second fraction (Fraction B). The result appears instantly below — no button to press.
You can type negative numbers in any box, and improper fractions like 7/2 are perfectly fine. Leave a numerator blank and it is treated as 0. Every answer is automatically reduced to its lowest terms.
The fraction formulas
Behind the scenes the tool uses the classic rules. Addition:a/b + c/d = (a·d + c·b) / (b·d). Subtraction is the same with a minus sign.Multiplication: a/b × c/d = (a·c) / (b·d). Division:a/b ÷ c/d = (a·d) / (b·c) — that is, multiply by the reciprocal of the second fraction. After computing the raw result it divides the numerator and denominator by their greatest common divisor (GCD) so the fraction is always shown in simplest form.
Fraction, mixed number and decimal
The same answer is shown three ways so you can use whichever you need. The simplified fraction is the reduced form, for example 5/6. The mixed number splits an improper fraction into a whole part and a proper fraction, so 7/3 becomes 2 1/3. The decimal is the numerator divided by the denominator, rounded for readability — handy when you need to plug the value into another calculation.
Handling zero and errors
A fraction is undefined when its denominator is 0, so the calculator shows a clear error if either denominator is left at zero. Division is also undefined when the second fraction equals zero (a zero numerator over any denominator), and that case is caught too. Fix the highlighted input and the result reappears immediately.
Is it private?
Yes. The Fraction Calculator is plain JavaScript that runs entirely inside your browser tab. The numbers you enter are never uploaded, logged or stored anywhere — there are no accounts and no tracking of your inputs. Once the page has loaded you can even use it offline.
Frequently asked questions
Can it work with negative fractions?
Yes. Type a minus sign in any numerator or denominator. The result keeps the correct overall sign and is shown with the negative on the whole value.
What is an improper fraction?
An improper fraction has a numerator larger than its denominator, like 7/3. The calculator accepts these and also shows the equivalent mixed number, e.g. 2 1/3.
Why does it show a dash and an error?
That happens when a denominator is 0 (a fraction can't have a zero denominator) or when you divide by a fraction that equals zero. Correct the input and the answer returns.
Decimal results are rounded for display; for exact work use the fraction form.