GCD & LCM Calculator
Find the greatest common divisor (GCD) and least common multiple (LCM) of two positive integers. Free and private, right in your browser.
Enter two or more numbers to instantly get their greatest common divisor and least common multiple, with the steps shown, handy for simplifying fractions, syncing repeating events, or solving ratio and scheduling problems.
How to use it
- Type in two or more whole numbers, separated by commas or spaces
- Get the GCD and LCM calculated instantly as you type
- Check the breakdown to see how each result was derived
Frequently asked questions
- What's the difference between GCD and LCM?
- GCD (greatest common divisor) is the largest number that divides all your inputs evenly, useful for reducing a fraction like 24/36 to its simplest form. LCM (least common multiple) is the smallest number that all your inputs divide into evenly, useful for finding when repeating events line up, like two lights that blink every 4 and 6 seconds.
- Can I calculate GCD and LCM for more than two numbers at once?
- Yes, enter as many numbers as you need (e.g. 12, 18, 30) and it computes the GCD and LCM across the whole set, not just pairs.
- Does it show the work, like prime factorization?
- Yes, alongside the final answer you'll see the factorization-based breakdown so you can verify the result or use it for homework.
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Nothing is uploaded
The file never leaves your device. There is no server to send it to, so there is nothing to leak, log, or subpoena.
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No signup, no limits
No account, no email, no daily cap, no watermark, and no paid tier waiting behind the third file.
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Works offline
Load the page once and it keeps working with the network off, because all the work was always happening locally.