Least Common Multiple Calculator
The least common multiple, or LCM, is the smallest whole number that both of your numbers divide into evenly. It is handy when adding fractions or lining up repeating events.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
List the multiples of each number and pick the first one they share. Another way: multiply the two numbers together and divide by their greatest common factor.
For example, twelve and eighteen share a factor of six, so twelve times eighteen, divided by six, gives thirty-six.
Worked example
The least common multiple of 12 and 18 is 36.
Questions
How is the LCM different from the GCF?
The greatest common factor is the largest number that divides both. The least common multiple is the smallest number that both divide into.
Why is it useful for fractions?
Fractions with a common denominator are easy to add. The LCM of the denominators is the smallest such denominator.
What about three numbers?
Find the LCM of the first two, then find the LCM of that answer and the third number. This page takes two numbers.
More like this
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- Percent Change CalculatorPercent up or down between two numbers.
- Average CalculatorMean of a list of numbers.
- Percent Difference CalculatorGap between two values, as a share of their average.
- Standard Deviation CalculatorSpread of a list of numbers.
- Weighted Average CalculatorAverage where some values count more.