Fraction Calculator

How Fraction Calculator works

Do fraction arithmetic and get the answer simplified to lowest terms with its decimal value. Everything happens inside this page: the tool reads your input, runs the calculation or conversion locally, and hands the result back to you. Nothing is transmitted, because there is no backend to transmit it to.

That design choice is deliberate. Most free tool sites upload your files to a server, process them there, and quietly keep a copy. Toolcin cannot do that — the site is a set of static files. If your connection dropped the moment the page finished loading, every tool would still work.

Four operations, one reduction

Enter a numerator and denominator on each side, choose +, −, × or ÷, and the result is shown reduced to lowest terms. The arithmetic follows the standard rules: a common denominator for addition and subtraction, multiply across for multiplication, and multiply by the reciprocal for division.

Reduction uses the greatest common divisor, computed with the Euclidean algorithm. 6/8 becomes 3/4, and 12/18 becomes 2/3, so the answer is a fraction you can actually use rather than a technically correct 18/24.

Division by zero and negative values

A zero denominator is rejected on either side, because division by zero is undefined and any answer would be a fiction. A zero numerator is fine: 0/5 is 0.

Negative numerators work. The result keeps the sign in the numerator by convention — −1/2 rather than 1/−2 — which is how most textbooks and calculators present it. Mixed numbers are not used, because a single improper fraction is easier to check.

When the fraction is the better answer

Decimal answers lose exactness the moment the denominator is not a power of 2 or 5. 1/3 is 0.333… forever; the fraction carries the exact value. In recipes, carpentry and anywhere you scale a measurement up and down repeatedly, the fraction is the honest form.

For a final measurement on a tool, convert to a decimal — tape measures read decimals and fractions inconsistently, and mixing them is how a cut ends up short.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions