Least Common Denominator Calculator
Find the least common denominator (LCD) of two to six denominators by calculating their least common multiple.
Least Common Denominator Calculator
Enter two or more denominators separated by commas, spaces, or semicolons.
How it works
Formula and steps
The formula shows how the least common denominator calculator turns your inputs into the result. Use it to check the calculation, then follow the example steps to see each part of the math.
Formula & steps
Least common denominator formula
LCD = LCM of the denominators
The least common multiple of the entered denominators is their least common denominator.
LCD= Least common denominatorLCM= Least common multipledenominators= Positive bottom numbers of the fractions- 1Enter two to six positive whole-number denominators.
- 2Find the least common multiple (LCM) of those values.
- 3Use that least common multiple as the least common denominator.
- 4Rewrite each fraction as an equivalent fraction over the LCD before adding or subtracting.
Worked examples
The LCD of 4, 6, and 8 is 24.
The LCD of 3, 5, and 12 is 60.
Common uses
- Adding unlike fractions
- Subtracting unlike fractions
- Comparing fractions
- Finding a common denominator
Common mistakes
- Multiplying all denominators when a smaller common denominator exists.
- Confusing the least common denominator with the greatest common factor.
- Entering zero, a negative number, or a decimal as a denominator.
Fraction guide
How to find the least common denominator
The least common denominator is the smallest positive denominator shared by equivalent forms of all the fractions in a problem.
Find the LCM of the denominators
The least common denominator is the least common multiple of the entered positive whole-number denominators.
Use the least common multiple calculator →Use the LCD with unlike fractions
Rewrite each fraction over the LCD before adding, subtracting, or comparing fractions with different denominators.
Supported denominators
Enter between two and six positive whole numbers separated by commas, spaces, or semicolons.
FAQ
Find the least common multiple of all denominators. That number is their least common denominator.
The LCD is the LCM of the denominators in a fraction problem. LCM is the general number relationship; LCD is its use with fractions.
Enter between two and six positive whole-number denominators separated by commas, spaces, or semicolons.
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