Fraction Calculator Calculators
Add, subtract, multiply and divide fractions, simplified automatically.
Fraction Calculator is a free online tool that add, subtract, multiply and divide fractions, simplified automatically. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Calculators
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 5
- Works offline
- Yes, after the first visit
About Fraction Calculator
Results are reduced automatically using the greatest common divisor, so 6/8 comes back as 3/4 rather than left as-is. Division is implemented as multiplication by the reciprocal, which is the same rule you were taught as "invert and multiply" — worth remembering that it is a rule with a reason, not a trick.
How to use it
- Enter numerator 1, denominator 1 and operation.
- Adjust the remaining 2 settings if the defaults do not fit your case.
The 5 settings
| Setting | What it does | Default |
|---|---|---|
| Numerator 1 | A numeric value. | 1 |
| Denominator 1 | A numeric value. | 2 |
| Operation | Choose from 4: +, −, ×, ÷. | + |
| Numerator 2 | A numeric value. | 1 |
| Denominator 2 | A numeric value. | 3 |
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
| Controls | Numerator 1, Denominator 1, Operation, Numerator 2, Denominator 2 |
Questions
Why do I get a whole number and a remainder?
Improper fractions are also shown as mixed numbers. 7/3 is 2 1/3 — same value, and usually easier to picture.
What does the operation option change?
It offers 4 choices — +, −, × and ÷. The default is +, which suits most cases; change it when your input or your destination calls for something specific.
Is the arithmetic exact?
It uses double-precision floating point — about 15 significant figures, far more than the inputs justify. Displayed rounding is cosmetic; the underlying numbers are not rounded between steps, so chained results do not drift.