On this page is a *least or lowest common denominator calculator. *Enter fractions or positive integers, and the tool will return the lowest common denominator (LCD) of each term and list the new form of each number in the results.

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## Lowest Common Denominator (LCD) Calculator

**Table of Contents**show ▼

## What is the Least or Lowest Common Denominator (LCD)?

The *least* or *lowest common denominator* (LCD) is the smallest number which is a multiple of every denominator in the set. Expressing each fraction or number in a set in terms of a common denominator simplifies math on those numbers.

The lowest common denominator is sometimes – but not always – the product of every denominator. Other times, it is one of the denominators already in the set.

## Finding the Lowest Common Denominator

Let's find the LCD – using a brute force multiplication method – for the 4 numbers included in the tool: 2/3, 10, 12/5, and 4.

(Note that we can rewrite the integers as fractions over '1': 2/3, 10/1, 12/5, and 4/1.)

Strip the denominators out and multiply:

Now, rewrite each fraction with a denominator of 15. (Multiplying the numerator and denominator by the same amount):

At this point, you can now reduce each fraction by finding common factors. However, you can't here – 36, 10, 150, and 60 share no factors other than 1.

## Using the Lowest Common Denominator Calculator

In the text box, enter your list of numbers to find the lowest common factor. You can enter whole numbers, fractions (using '/'), negatives, and decimals – but fractions and positive numbers make the most sense.

Next, press the **Compute LCD** button. We'll return the Lowest Common Denominator and the total count of numbers we understood..

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