Fraction Calculator

Add, subtract, multiply and divide fractions and mixed numbers, then simplify and convert the answer to a mixed number, decimal and percentage.

Reviewed by Dany, RightSums team · Updated

Runs in your browser. Free, no sign-up.

maths · Daily life · UK & US

Enter two fractions, mixed numbers, whole numbers or decimals, choose add, subtract, multiply or divide, and the calculator shows the answer with every step. Mixed numbers are turned into improper fractions first. For adding and subtracting it finds the lowest common denominator and rewrites both fractions over it. For multiplying it multiplies the tops and the bottoms, and for dividing it flips the second fraction and multiplies. It then simplifies by dividing by the greatest common factor and gives the answer as a fraction, a mixed number, a decimal and a percentage. Repeating decimals show the repeating digits in brackets, so 5/6 is 0.8(3). You can also simplify or convert a single fraction. The arithmetic is exact, with no rounding.

Accepted inputs

  • Fractions such as 3/4
  • Mixed numbers such as 1 1/2
  • Whole numbers, negatives and decimals
  • Operation: add, subtract, multiply, divide or simplify

Outputs

  • Answer as a simplified fraction
  • Mixed number
  • Exact or repeating decimal
  • Percentage
  • Step-by-step working

How to use the Fraction Calculator

  1. Type two fractions, mixed numbers, whole numbers or decimals and pick an operation.
  2. Mixed numbers become improper fractions, and for adding or subtracting both fractions are rewritten over the lowest common denominator.
  3. Multiplying multiplies the tops and bottoms, while dividing flips the second fraction and multiplies.
  4. The answer is simplified by the greatest common factor and shown as a fraction, mixed number, decimal and percentage.

Frequently asked questions

How do you add fractions with different denominators?

Rewrite both fractions over the lowest common denominator, then add the tops. For 1/2 + 1/3 the lowest common denominator is 6, so 1/2 = 3/6 and 1/3 = 2/6. Then 3/6 + 2/6 = 5/6, which is already in its simplest form.

How do you add mixed numbers?

Turn each mixed number into an improper fraction, add, then convert back. For 1 1/2 + 2 3/4: 1 1/2 = 3/2 = 6/4 and 2 3/4 = 11/4. Then 6/4 + 11/4 = 17/4, and 17 ÷ 4 = 4 remainder 1, so the answer is 4 1/4.

How do you divide fractions?

Flip the second fraction and multiply. For 3/4 ÷ 2/5, flip 2/5 to get 5/2, then 3/4 × 5/2 = 15/8. As a mixed number that is 1 7/8, and as a decimal 1.875. People often remember it as keep, change, flip.

How do you simplify a fraction?

Divide the top and bottom by their greatest common factor. For 18/24 the GCF is 6, so 18/24 = (18 ÷ 6)/(24 ÷ 6) = 3/4. A fraction is in its simplest form when the only number that divides both parts is 1.

How do you subtract mixed numbers?

Change both to improper fractions, use a common denominator, then subtract. For 2 1/3 − 1 3/4: 2 1/3 = 7/3 = 28/12 and 1 3/4 = 7/4 = 21/12. So 28/12 − 21/12 = 7/12, which is 0.58(3) as a decimal.

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