GCD and LCM Calculator Calculators
Greatest common divisor and lowest common multiple of any list of integers.
GCD and LCM Calculator is a free online tool that greatest common divisor and lowest common multiple of any list of integers. 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
- None — it just works
- Works offline
- Yes, after the first visit
About GCD and LCM Calculator
The greatest common divisor is found with the Euclidean algorithm, which is roughly 2,300 years old and still the fastest practical method — it replaces the larger number with the remainder repeatedly until one divides the other. The lowest common multiple comes from the identity LCM(a,b) = |a × b| ÷ GCD(a,b).
How to use it
- Paste the text you want to run through gcd and lcm calculator.
- There is nothing to configure — the result updates as you type.
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
Questions
What are these actually used for?
GCD reduces fractions to lowest terms and simplifies ratios. LCM finds the common denominator when adding fractions, and answers scheduling questions — two buses every 12 and 18 minutes coincide every 36.
Can I use negative numbers?
Yes, and the result is always positive. Sign is irrelevant to divisibility, so GCD(−12, 18) is 6 just as GCD(12, 18) is.
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.