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Fraction Calculator: Add, Subtract, Multiply and Divide

This free fraction calculator adds, subtracts, multiplies and divides fractions and mixed numbers. It simplifies the answer and shows it as a fraction, a mixed number and a decimal.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

A fraction shows a part of a whole as one whole number over another. Fractions appear in recipes, measurements, carpentry, school maths and music. Adding and dividing them by hand is slow and mistakes are common, mostly with the denominators.

This calculator accepts proper fractions, improper fractions, mixed numbers, whole numbers and decimals, and always returns a simplified result.

How to Use This Tool

  1. Type the first fraction, for example 3/4 or 1 1/2.
  2. Choose add, subtract, multiply or divide.
  3. Type the second fraction.
  4. Press Calculate to see the answer in three forms.

How the Calculation Works

Add or subtract: a/b ± c/d = (ad ± cb) / bd. Multiply: a/b × c/d = ac / bd. Divide: a/b ÷ c/d = ad / bc. The result is divided by the greatest common divisor of top and bottom.

Mixed numbers are first turned into improper fractions: 1 3/4 is (1 × 4 + 3) / 4 = 7/4. A decimal such as 0.75 becomes 75/100 and is then simplified to 3/4.

Worked Example

Add 1/2 and 2/3. The calculator works out (1 × 3 + 2 × 2) / (2 × 3) = 7/6. As a mixed number that is 1 1/6, and as a decimal about 1.166667.

Divide 3/4 by 1/8: 3/4 × 8/1 = 24/4 = 6.

Common Uses

  • Scaling a recipe from 4 servings to 6.
  • Adding lengths in inches, such as 5/8 and 3/16.
  • Checking school homework.
  • Working with ratios and probabilities.

Tips and Common Mistakes

  • A denominator of zero is not allowed, and the tool will tell you.
  • Negative fractions are allowed: type the minus sign in front.
  • To compare two fractions, subtract them and look at the sign of the answer.

Next, you may need the percentage calculator, ratio calculator, GCD and LCM calculator, average calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

Find a common denominator, rewrite each fraction with it, add the top numbers and keep the denominator. 1/2 + 1/3 = 3/6 + 2/6 = 5/6.
Flip the second fraction and multiply. 1/2 ÷ 3/4 = 1/2 × 4/3 = 4/6 = 2/3.
Yes. Type 2 1/3 for a mixed number, or 0.75 for a decimal. The tool turns both into fractions first.
The tool divides top and bottom by their greatest common divisor so the fraction is as simple as it can be.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.