Fraction Calculator: Add, Subtract, Multiply and Divide Fractions

Every calculation on this page follows one of four rules, where the first fraction is a/b and the second is c/d:

Operation	Rule	Example
Add	(a × d + b × c) / (b × d)	1/2 + 1/3 = (3 + 2)/6 = 5/6
Subtract	(a × d − b × c) / (b × d)	5/6 − 1/6 = 4/6 = 2/3
Multiply	(a × c) / (b × d)	3/4 × 2/3 = 6/12 = 1/2
Divide	(a × d) / (b × c) — flip the second fraction, then multiply	3/4 ÷ 1/2 = (3 × 2)/(4 × 1) = 6/4 = 3/2

After applying the rule, the calculator divides the top and bottom of the answer by their greatest common divisor (GCD), which puts the result in lowest terms. For example, 6/12 becomes 1/2 because GCD(6, 12) = 6.

Add 1/2 and 1/3 by hand:

1. Apply the addition rule: (1 × 3 + 2 × 1) / (2 × 3) = (3 + 2)/6 = 5/6.
2. Simplify: GCD(5, 6) = 1, so 5/6 is already in lowest terms.
3. As a decimal: 5 ÷ 6 = 0.8333 (to 4 decimal places).

So 1/2 + 1/3 = 5/6 ≈ 0.8333 — exactly what the calculator above shows when you enter 1, 2, +, 1, 3.

Type two fractions and choose an operation. The calculator handles the common-denominator work and the simplification for you.

Step by step

1. Enter the first fraction — the numerator on top, the denominator below. Use whole numbers only, for example 3 over 4.
2. Pick an operation: Add (+), Subtract (−), Multiply (×) or Divide (÷).
3. Enter the second fraction the same way.
4. Press Calculate. The result appears with the simplified fraction, the mixed number when there is one, the decimal to 4 places, and the full step-by-step working.

What you get

• Simplified fraction — always in lowest terms
• Mixed number — shown when the answer is an improper fraction, for example 3/2 becomes 1 1/2
• Decimal — rounded to 4 decimal places
• Step-by-step working — the rule used, the un-simplified result, and the GCD step

Entry rules

All four boxes accept whole numbers, including negatives. Decimals are rejected, and denominators must not be zero — a denominator of 0 makes a fraction undefined. When dividing, the second fraction must not be 0 either, since that means dividing by zero.

A fraction is in simplest (lowest) terms when the numerator and denominator share no common factor except 1. To simplify, find the greatest common divisor (GCD) of the two numbers and divide both by it:

1. Find the GCD of the numerator and denominator. For 6 and 8 it is 2; for 6 and 12 it is 6.
2. Divide both numbers by the GCD: 6 ÷ 2 = 3 and 8 ÷ 2 = 4, so 6/8 becomes 3/4.
3. Check: 3 and 4 share no common factor except 1, so 3/4 is in lowest terms.

For a visual walkthrough of equivalent fractions, the fractions guide at Maths is Fun is a clear, beginner-friendly reference. The calculator on this page performs the GCD step for you on every answer, so 5/6 − 1/6 = 4/6 is reported as 2/3 without you having to reduce it yourself.

To turn a fraction into a decimal, divide the numerator by the denominator. To turn it into a percent, multiply that decimal by 100. Here are the equivalents you will meet most often:

Fraction	Decimal	Percent
1/2	0.5000	50.0%
1/3	0.3333	33.3%
2/3	0.6667	66.7%
1/4	0.2500	25.0%
3/4	0.7500	75.0%
1/5	0.2000	20.0%
2/5	0.4000	40.0%
1/8	0.1250	12.5%
3/8	0.3750	37.5%
5/8	0.6250	62.5%
7/8	0.8750	87.5%
1/10	0.1000	10.0%

When a discount or a rate is easier to read as a percent than as a fraction — 3/4 off is 75% off — our percentage calculator picks up where this page leaves off.

An improper fraction has a numerator larger than its denominator, like 3/2 or 7/4. A mixed number writes the same value as a whole number plus a proper fraction: 3/2 = 1 1/2, and 7/4 = 1 3/4.

Converting 3/2 to a mixed number

1. Divide: 3 ÷ 2 = 1 with a remainder of 1.
2. The whole number is 1, the remainder 1 becomes the new numerator, and the denominator stays 2.
3. Result: 1 1/2.

Negative results keep the minus sign in front of the whole number: −3/2 becomes −1 1/2. If a calculation mixes fractions with decimals, powers or roots, a scientific calculator is the right tool for the follow-up work.