Fraction Calculator — Add, Subtract, Multiply, Divide and Compare, With Steps

How to use the fraction calculator

1. Type the First fraction, such as 3/4, 1 1/2, 0.6 or 2.
2. Choose an Operation: add, subtract, multiply, divide or compare.
3. Type the Second fraction.
4. Read the Result in its simplest form, plus the Mixed number, Decimal and Percent.
5. Follow the Steps to see how the answer was reached, which is handy for checking homework.

What it does and when to use it

Fractions turn up in homework, recipes, woodwork and measurements in inches. The arithmetic is not hard, but common denominators and simplifying take time and are easy to slip up on. This calculator does the work and shows it, so you can learn the method as well as get the answer.

Use it to:

• Check maths homework step by step.
• Scale a recipe, for example 2 1/4 cups × 4/9.
• Add up measurements such as 3/8 inch + 5/16 inch.
• Find out which of two fractions is bigger.
• Turn a fraction answer into a decimal or a percentage.

To turn a decimal like 0.1666… into a fraction, use Decimal to Fraction. To find common factors and multiples, the GCD and LCM Calculator helps. For percentage questions, see the Advanced Percentage Calculator.

How it works

Every input is turned into an exact fraction made of two whole numbers. Mixed numbers become improper fractions (1 1/2 becomes 3/2) and decimals become fractions over a power of ten (0.6 becomes 3/5).

• Add or subtract: find the LCD of the two denominators, rewrite each fraction over it, combine the numerators, then divide top and bottom by their greatest common divisor (GCD).
• Multiply: multiply the numerators and the denominators, then simplify.
• Divide: multiply by the reciprocal of the second fraction, then simplify.
• Compare: cross-multiply and compare the two products.

Because the tool uses exact whole-number arithmetic, very large numerators and denominators stay exact. It all runs in your browser.

Worked examples

Adding with different denominators. 3/4 + 5/6. The steps are LCD = 12, then 3/4 = 9/12 and 5/6 = 10/12, then 9/12 + 10/12 = 19/12. The result is 19/12, or Mixed number: 1 7/12, which is 1.58(3) as a decimal.

Dividing a mixed number. 1 1/2 ÷ 3/8 becomes 3/2 × 8/3 = 24/6, which simplifies to Result: 4. Three-eighths fits into one and a half exactly four times.

Scaling a recipe. 2 1/4 × 4/9 = (9 × 4) ÷ (4 × 9) = 36/36 = 1. So 4/9 of 2 1/4 cups is exactly 1 cup.

Comparing a fraction and a decimal. 2/3 against 0.6. The tool reads 0.6 as 3/5, cross-multiplies (10 against 9) and shows Comparison: 2/3 > 3/5, a difference of 1/15.

Limits and tips

• Write one fraction per box. Expressions such as “1/2 + 1/3” in a single box are not supported.
• Dividing by zero is undefined, and the tool will say so.
• Negative fractions work. Type a minus sign in front, such as -3/4.