Find the least common multiple of any numbers. This free LCM calculator returns the smallest value they all divide into, and shows the greatest common factor too.”
Your numbers
Enter two or more whole numbers. The LCM is the smallest positive number that every value divides into evenly.
Least common multiple
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Enter some numbers
Numbers used
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GCF (greatest common factor)
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Count
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Product of all
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The LCM is useful for adding fractions (a common denominator) and for problems where events repeat on different cycles. It uses whole numbers; decimals are rounded.
Use this free LCM calculator to find the least common multiple of two or more numbers. Enter your values and it returns the smallest number they all divide into, plus the GCF.
What this LCM calculator does
An LCM calculator finds the least common multiple — the smallest positive number that every value in your list divides into evenly. It works for two or more whole numbers and also shows the greatest common factor.
How the LCM is calculated
LCM(a, b) = (a × b) ÷ GCD(a, b)
For more numbers, apply this in turn
The LCM of 4 and 6 is 12; the LCM of 4, 6 and 8 is 24. The calculator chains the rule across as many numbers as you enter.
LCM examples
Numbers
LCM
3, 5
15
4, 6, 8
24
12, 18, 24
72
2, 3, 4, 5
60
What is the LCM used for?
The most common use is adding or subtracting fractions — the LCM of the denominators gives the lowest common denominator. It also solves “when do cycles line up?” problems, like two events that repeat every few days.
How to use the LCM calculator
Enter two or more numbers, separated by commas, spaces or new lines.
Read the least common multiple.
See the GCF shown alongside.
LCM FAQ
How do I find the LCM?
One reliable way: LCM(a, b) = (a × b) ÷ GCD(a, b), applied across all your numbers. The LCM of 4 and 6 is 24 ÷ 2 = 12. The calculator handles any number of values.
What is the least common multiple?
It's the smallest positive number that every number in your set divides into without a remainder. For 4, 6 and 8 it's 24.
What is the LCM used for?
Most often for adding fractions — the LCM of the denominators is the lowest common denominator. It also solves problems where repeating cycles line up.
What's the difference between LCM and GCF?
The LCM is the smallest number all your values divide into; the GCF is the largest number that divides into all of them. This calculator shows both.
Can I find the LCM of more than two numbers?
Yes. Enter as many whole numbers as you like, separated by commas, spaces or new lines, and it finds the LCM of all of them.
Is the LCM calculator free?
Yes, this LCM calculator is completely free, needs no sign-up, and gives instant results in your browser.
