Use this calculator to find the least common denominator of fractions, integers and mixed numbers. We also have calculators for least common multiple, fraction operations, simplifying fractions, mixed numbers operations, and comparing fractions. See additional notes below.

How to Find the LCD of Fractions, Integers and Mixed Numbers:

To find the LCD first convert all integers and mixed numbers (mixed fractions) into fractions.  Then find the least common multiple (LCM) of the denominators which is equal to the least common denominator (LCD).  You can then rewrite each term as an equivalent fraction with the LCD.

Steps to find the LCD of fractions, integers and mixed numbers

Convert integers and mixed numbers to improper fractions

Find the LCD of all the fractions

Rewrite fractions as equivalent fractions using the LCD

Example using this calculator default sample:

Input: 1 1/2, 3/8, 5/6, 3

Convert integers and mixed numbers to improper fractions

3/8 and 5/6 are already fractions so we can use those as they are written.

1 1/2 is the same as (1/1) (1/2). Using the formula for adding fractions, ((n1*d2) (n2*d1)) / (d1*d2), we get ((1*2) (1*1)) / (1*2) = 3/2

3 rewritten as a fraction can be 3/1.

Input rewritten as fractions is: 3/2, 3/8, 5/6, 3/1

Now find the least common denominator (LCD) (or the least common multiple (LCM) of the denominators)

LCD = 24

Rewriting the fractions as equivalent fractions using the LCD

36/24, 9/24, 20/24, 72/24

Further Reading