How it works
Common methods include prime factorization (take each prime at its highest power) or the Euclidean algorithm link through GCF. The calculator automates that for your inputs.
Formula
LCM(a,b) = |a × b| ÷ GCF(a,b); for lists, LCM is associative
How to use LCM Calculator
- Enter two or more whole numbers separated or in separate fields.
- Run the calculation.
- Review the LCM result and any prime-factor or multiple listing shown.
- Use the GCF tool if you also need the greatest common factor.
Worked examples
Concrete numbers and cases you can check against the tool above.
Common denominator for 5/12 + 7/18
LCM(12, 18) = 36. Convert to 15/36 + 14/36 = 29/36 without guessing a denominator.
When to use LCM Calculator
Listing multiples by hand is slow for large numbers. LCM also feeds GCF relationships: LCM(a,b) × GCF(a,b) = |a×b| for two integers.
Common use cases
- Find a common denominator for 1/6 + 1/8.
- Schedule repeating events that happen every 4 and 6 days.
- Solve textbook LCM word problems with verification.
Inputs and outputs
- Positive integers (negative inputs may use absolute value)
- Two or more numbers at once
Privacy
This tool runs entirely in your browser. Your data never leaves your device — nothing is uploaded to our servers.
Frequently asked questions
- What is LCM vs GCF?
- LCM is the smallest shared multiple; GCF is the largest shared factor. They solve different problems but share the same prime building blocks.
- Can LCM be smaller than the largest input?
- No. The LCM is always at least as large as the greatest input number (for positive integers).
- What about zero?
- LCM with zero is not meaningful in standard grade-school definitions; valid tools require positive integers.