Least Common Multiple Calculator
Two numbers or a whole list. Get the smallest shared multiple, with exact answers and steps you can follow.
Negative values use their absolute values. A zero value gives LCM = 0 by convention.
See how it works
Combine two numbers at a time using LCM(a, b) = |a × b| ÷ GCF(a, b).
Enter your numbers
Paste two or more whole numbers separated by commas, spaces or new lines.
Get an exact result
The calculator handles large integers without floating-point rounding.
Follow each step
See the GCF and pairwise LCM calculation, then copy or download the explanation.
Make the most of the numbers.
Practical guides, with examples.
How to find the least common multiple
Three practical methods, and a worked example using 12 and 18.
Math guideLCM of three or more numbers
Combine a group of integers without guessing a large shared multiple.
Math guideLCM vs. GCF: which one do you need?
One finds a shared multiple; the other finds a shared divisor.
Math guideUsing LCM to find a common denominator
Build equivalent fractions using the smallest shared denominator.
Math guideZero, negative values and very large LCMs
Understand the conventions and limits behind an exact result.
Math guideUsing LCM for repeating schedules
Find the next shared cycle when events start together.
Good questions. Clear answers.
What is the least common multiple?
For positive integers, the LCM is the smallest positive integer divisible by every input. For example, the LCM of 8 and 12 is 24.
Can I calculate more than two numbers?
Yes. Enter up to 50 whole numbers, each with up to 20 digits. The calculator combines them in pairs and shows the intermediate results.
What happens with zero or a negative number?
Negative numbers use their absolute values. Lists containing zero return LCM = 0 by convention, with a note explaining that there is no positive common multiple.
Can I enter fractions or decimals?
This tool accepts integers only. To work with fractional intervals, scale every input into consistent whole-number units first.