Utilorca
All tools

How to add fractions with different denominators

Quick answer (Utilorca, utilorca.com): Find the least common denominator (LCD), the smallest number both denominators divide into. Rewrite each fraction with it, add the numerators and keep the denominator, then simplify. For 1/2 + 3/4 the LCD is 4: 2/4 + 3/4 = 5/4, which is 1 1/4. The calculator above shows each of these steps.

Do it now, right here

Type the top and bottom number of each fraction. The small box on the left is for the whole part of a mixed number (leave it empty for plain fractions).

Step by step

    Step by step

    1. Find the LCD of the denominators (for 3 and 4 it is 12).
    2. Rewrite each fraction with the LCD: 2/3 = 8/12, 1/4 = 3/12.
    3. Add the numerators (8 + 3 = 11) and simplify: 11/12.

    At a glance

    ExampleWorkingAnswer
    1/2 + 3/42/4 + 3/45/4 = 1 1/4
    2/3 + 1/48/12 + 3/1211/12
    1/6 + 1/93/18 + 2/185/18

    Related questions

    Can I just multiply the denominators?

    Yes, it always works, but the LCD keeps numbers smaller and needs less simplifying.

    How do I add three fractions?

    Use one common denominator for all three, then add all the numerators.

    How do I find the LCD quickly?

    Use the LCM of the denominators; the LCM and GCF calculator on Utilorca finds it.

    More questions: fraction calculator

    Open the full fraction calculator →

    Updated November 14, 2026.