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Enter numbers
Add two or more whole numbers separated by commas, spaces, tabs, or new lines.
Free LCM Calculator
An LCM calculator finds the least common multiple, the smallest positive number that every entered non-zero whole number divides evenly into. Enter two or more numbers to see the answer, prime factors, and each calculation step.
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Least common multiple calculator
Enter two or more whole numbers
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Classroom note
LCM uses absolute values, so negative signs do not change the result. If any entered value is zero, the LCM is zero.
LCM result
Least common multiple
180
3 valid numbers checked
Absolute values used
12, 18, 30
Prime powers selected
2^2 × 3^2 × 5
Prime-power method
Use each prime at its highest needed power: 2^2 × 3^2 × 5.
2^2 = 43^2 = 95
NumberPrime factors
122^2 × 3
182 × 3^2
302 × 3 × 5
Pair-by-pair check
- 1. LCM(12, 18) = 36 using GCF 6
- 2. LCM(36, 30) = 180 using GCF 6
How to Use the LCM Calculator
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Compare prime factors
See the prime factorization and highest exponent needed for each prime.
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Use the LCM
Copy or download the exact result and steps for a lesson or homework check.
LCM Calculator FAQ
What is an LCM calculator?
An LCM calculator finds the least common multiple, which is the smallest positive number that every entered non-zero whole number divides evenly into.
How do you find the LCM using prime factors?
Prime-factor each number, keep every prime at the highest exponent used, and multiply those selected prime powers together.
Can I calculate the LCM of more than two numbers?
Yes. Enter up to 20 whole numbers, and the calculator combines their highest prime powers to find one shared multiple.
What is the LCM when one number is zero?
The LCM is zero when any entered number is zero because zero is the only non-negative common multiple in that set.
How is LCM different from GCF?
LCM is the smallest shared multiple, while GCF is the largest whole number that divides every value without a remainder.