LCM Calculator (Least Common Multiple)
Enter two or more positive whole numbers to find their least common multiple. The calculator uses the lcm(a, b) = |a x b| / gcd(a, b) identity and folds it across the list.
How to find the least common multiple
- Type your positive integers separated by commas or spaces.
- Read the LCM, the smallest number that every value divides into.
- Copy the result or change a number to recompute instantly.
Examples
LCM of two numbers
4, 6
12
LCM of a longer list
3, 4, 5
60
Frequently asked questions
What is the least common multiple?
The least common multiple (LCM) of a set of integers is the smallest positive integer that every one of them divides into evenly.
How is the LCM calculated?
For two numbers, LCM equals their product divided by their greatest common divisor: lcm(a, b) = |a x b| / gcd(a, b). For a longer list the calculator folds this rule across every value.
Why does the calculator require positive integers?
The multiple of zero is always zero, so the LCM is undefined when any value is zero. The tool requires positive whole numbers to keep the answer meaningful.
How is the LCM useful for fractions?
The LCM of the denominators is the least common denominator, which lets you add or compare fractions without changing their values.
What is the LCM of two coprime numbers?
When two numbers share no common factor, their GCD is 1 and the LCM is simply their product, such as lcm(2, 7) = 14.
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