LCM calculator
Find the least common multiple of two integers using exact integer arithmetic. Negative inputs are handled by magnitude.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| First integer | Use a whole number in the stated format. Fractions and rounding are not interchangeable with exact integer inputs. |
| Second integer | Use a whole number in the stated format. Fractions and rounding are not interchangeable with exact integer inputs. |
Understanding your result
Read Least common multiple in the units and model stated on this page. The formula lcm(a, b) = |a × b| ÷ gcd(a, b) defines the relationship; measurement accuracy and model applicability are separate from numerical precision.
Common mistakes
- Using a different mathematical definition or operation than the one stated by this tool.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Calculation checks, sources and review limits
What is the smallest shared multiple of two numbers?
Enter two integers to find their least common multiple. For nonzero inputs, it is the smallest positive number divisible by both magnitudes.
Common uses
- Find a common denominator for fractions.
- Compare repeating cycles measured in the same unit.
How it works
Divide one input by the greatest common divisor before multiplying by the other. This avoids unnecessary intermediate growth. The result is non-negative. When either input is zero, this calculator uses an LCM of zero.
Worked example
LCM(12, 18) = |12 × 18| ÷ 6 = 36.