Subtract Fractions Calculator

Subtract one fraction from another by entering them below. Enter whole numbers by using a space between the whole number and the fraction.

Fraction One:
Fraction Two:

Result as a Fraction:


Result as a Decimal:


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How to Subtract Fractions

You can subtract one fraction from another in three easy steps.

Step One: Convert to Fractions with a Common Denominator

Illustration showing the first step in subtracting fractions by making the denominators match

The first step to subtracting fractions is to make the denominators of each fraction match. Convert each one to an equivalent fraction with a matching denominator to the other.

Find the Lowest Common Denominator

You’ll need to find the lowest common denominator for each of the fraction’s denominators. The lowest common denominator is the smallest number that each denominator can evenly divide into.

Find the Multiplier

Next, find the multiple for each denominator that can be multiplied to equal to the lowest common denominator. To find the multiple for each fraction, divide the least common denominator by denominator.

Multiply by the Multiplier

Then, multiply both the top and bottom number of the fraction the multiple to find the equivalent fractions with matching denominators. You can also use an equivalent fractions calculator to find one with a matching denominator.

For example, let’s convert the fractions 12 and 13 to fractions with the same denominator.

The least common denominator of 2 and 3 is 6.

Find the multiple for 12
multiple = lcd ÷ denominator
multiple = 6 ÷ 2 = 3

Find the equivalent fraction of 12 using the multiple 3
12 = 1 × 32 × 3
12 = 36

Find the multiple for 14
multiple = lcd ÷ denominator
multiple = 6 ÷ 3 = 2

Find the equivalent fraction of 13using the multiple 2
13 = 1 × 23 × 2
13 = 26

Thus, the equivalent fractions of 12 and 13 are 36 and 26

Step Two: Subtract the Numerators

illustration showing the second step in subtracting fractions by subtracting the numerator

Once the bottom numbers of each fraction match, subtract the top numbers from each together to find the result.

Simply subtract the second numerator from the first, then put the result over the common denominator.

For example, let’s continue the previous example and subtract 26 from 36.

3626 = 3-26
3626 = 16

Step Three: Simplify the Fraction

illustration showing the third step in subtracting fractions by simplifying

The final step to subtracting fractions is to reduce the result to its simplest form. Start by finding the greatest common factor of the top and bottom parts of the result.

Then, divide both the top and bottom numbers by the greatest common factor to reduce it. An even easier way to reduce is to use our fraction simplifier.

You can also subtract fractions using our fraction calculator.

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