The least common multiple is the first number that appears in every input’s list of multiples.
How to use the LCM Calculator
- First number
- Second number
- Third number (optional, 0 to skip)
Results update as you type, and every field accepts the units shown in its menu.
How it works
Divide the product of two numbers by their greatest common factor; repeat with the third number.
Inputs explained
| Field | What to enter |
|---|---|
| First number | A number |
| Second number | A number |
| Third number (optional, 0 to skip) | A number |
Formula
lcm(a, b) = |a × b| ÷ gcd(a, b)Worked example
Inputs — First number: 4; Second number: 6; Third number (optional, 0 to skip): 10.
Results — Least common multiple = 60; GCF of first two = 2.
Key terms
- Multiple
- The product of a number and an integer.
Frequently asked questions
How is LCM used with fractions?
The LCM of denominators is the least common denominator.
Is LCM always at least the largest number?
Yes.
What formula does the LCM Calculator use?
lcm(a, b) = |a × b| ÷ gcd(a, b).