LCM Calculator

Welcome to our LCM Calculator. When we set out to make the best online Least Common Multiple (LCM) Calculator ever created, we knew we had to do more than simply give you the option of entering two or three numbers and then calculate the LCM for you.

We believe we succeeded in creating the best LCM Calculator by not only giving you the option to enter more than two or three numbers, but also giving you information that you need to add or subtract fractions where the numbers you enter are the denominators of those fractions.

Basically, you will enter the denominators of the fractions that you want to add or subtract, and we will calculate the LCM (which will be the new denominator for the all the fractions). Then, we will tell you how much to multiply each numerator by to keep the fractions intact.

Example

The answer above gives you information you need to add or subtract fractions, because that is one of the main reasons to calculate LCM. To illustrate how the calculator works, let's assume you want to solve this fraction problem:

		2
		5

		3
		6

		4
		7

The numerators 2, 3, and 4 are above the fraction divider lines, and denominators 5, 6, and 7 are below the fraction divider lines.

To be able to solve this problem, we need to make the denominators the same and then add and subtract the numerators. We start by entering the denominators in our calculator above to get this:

LCM = 210: Make 210 the denominator for all your fractions.

5: If the denominator was 5, multiply the numerator by 42.
6: If the denominator was 6, multiply the numerator by 35.
7: If the denominator was 7, multiply the numerator by 30.

Now we follow the directions the calculator gave us:

		2 × 42
		210

		3 × 35
		210

		4 × 30
		210

After we calculate the numerators, we get this:

		84
		210

		105
		210

		120
		210

Now that the denominators are the same, we can add and subtract the numerators to get the answer:

		84 + 105 - 120
		210

		69
		210

There you have it folks. Not only did we calculate the LCM for you, but we also showed you how to add and subtract fractions using the LCM.

We hope you found our calculator useful. Note that the LCM Calculator is known by many names. In addition to the Least Common Multiple Calculator, it is also called the Lowest Common Multiple Calculator, or Smallest Common Multiple Calculator.