GCD & LCM Calculator
Find the greatest common divisor and least common multiple.
How to use
- 1 Enter two or more whole numbers, separated by spaces or commas.
- 2 See the greatest common divisor and least common multiple.
- 3 Add or remove numbers to update the results instantly.
- 4 Copy either value for your work.
About GCD & LCM Calculator
The GCD & LCM Calculator finds the greatest common divisor and the least common multiple of a list of whole numbers in one go.
Type as many integers as you like, separated by spaces or commas, and it returns both the largest number that divides them all and the smallest number they all divide into.
These two quantities sit behind a lot of everyday arithmetic.
The greatest common divisor is what you use to reduce a fraction or to split things into the largest equal groups.
The least common multiple is what you reach for when adding fractions with different denominators, lining up repeating schedules, or finding when two cycles coincide.
Computing them by listing factors is slow and easy to get wrong once the numbers grow.
This tool uses the Euclidean algorithm for the divisor and derives the multiple from it, working through your whole list pairwise.
Because least common multiples can grow very fast, the calculation uses big-integer arithmetic internally to stay exact and warns you rather than silently rounding if a result would exceed the safe range.
It accepts negatives by magnitude, runs entirely in your browser, and gives the same answer every time.
FAQ
What is the difference between GCD and LCM?
The GCD is the largest number that divides every input exactly; the LCM is the smallest number that every input divides into exactly.
Can I enter more than two numbers?
Yes. Enter as many whole numbers as you like and the tool computes the GCD and LCM across the whole list.
Does it handle large numbers?
Yes. It uses big-integer arithmetic internally to stay exact, and warns you if a least common multiple would exceed the safe display range.