Find the least common denominator for two or more fractions and rewrite each fraction with that shared denominator.
For 1/4 and 1/6, the denominators are 4 and 6. Their least common multiple is 12, so the LCD is 12.
The denominators 4 and 6 have least common multiple 12.
- Read denominators: 4 and 6.
- Find LCM(4, 6) = 12.
- Rewrite fractions as 3/12 and 2/12.
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How to Use the LCD Calculator
Enter two or more fractions separated by commas. The calculator reads each denominator, finds their least common multiple, and rewrites every fraction with the LCD.
- Enter fractions such as 1/4, 1/6.
- Find the LCM of the denominators.
- Rewrite each fraction with the common denominator.
Least Common Denominator Formula
The least common denominator is the least common multiple of the denominators in the fractions.
LCD Examples
1/4 and 1/6
LCM(4, 6) = 12, so the LCD is 12. The fractions become 3/12 and 2/12.
2/3, 5/6, and 7/9
The denominators are 3, 6, and 9. Their LCM is 18.
3/8 and 1/12
LCM(8, 12) = 24, so the LCD is 24.
Why LCD Helps with Adding Fractions
Fractions with unlike denominators cannot be added directly. The LCD gives a shared denominator so the numerators can be combined correctly.
Common LCD Mistakes
Using a common denominator that is not least
A larger common denominator can work, but the LCD keeps the numbers smaller.
Changing only the denominator
When rewriting a fraction, multiply the numerator and denominator by the same factor.
Confusing LCD with GCD
LCD uses the least common multiple of denominators. GCD finds a shared factor.
LCD Calculator FAQs
What is the LCD of 1/4 and 1/6?
The denominators are 4 and 6. Their least common multiple is 12, so the LCD is 12.
Can I enter more than two fractions?
Yes. Separate each fraction with a comma.
Can mixed numbers be used?
Yes. A mixed number is converted to an improper fraction before the denominator is used.
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Reviewer
This educational math content is reviewed under the SolverCalc reviewer rule by Prof. Dr. Khalil Mudassar. WordPress adds the author bio automatically, so this page does not include a duplicate author box.
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Disclaimer
This calculator is intended for general educational and practical use. Check exact fraction notation before using results in graded work.