Fraction Calculator
Add, subtract, multiply or divide two fractions and simplify the result.
Results update as you type.
About this calculator
A fraction calculator performs arithmetic on two fractions — addition, subtraction, multiplication and division — and returns the answer reduced to its lowest terms, as a decimal, and as a mixed number. Enter the numerator and denominator of each fraction, choose an operation, and the tool handles the cross-multiplication and simplification for you, showing the working line by line.
For addition and subtraction the two fractions are first rewritten over a common denominator (the product of the two denominators), the numerators are combined, and the result is divided by the greatest common divisor to simplify. Multiplication multiplies the numerators and the denominators straight across; division multiplies the first fraction by the reciprocal of the second. For example, 1/2 + 1/3 becomes 3/6 + 2/6 = 5/6, while 1/2 × 3/4 = 3/8 and 1/2 ÷ 3/4 = 1/2 × 4/3 = 4/6 = 2/3.
Exact fraction arithmetic comes up in cooking and recipe scaling, measuring in inches, splitting a bill, probability, and any classroom exercise where a precise answer beats a rounded decimal. Because the result is also shown as a decimal and a mixed number, you can read it in whichever form your problem needs.
Frequently asked questions
How do you add two fractions?
Give both fractions a common denominator, add the numerators, then simplify. 1/2 + 1/3 becomes 3/6 + 2/6 = 5/6.
How is the answer simplified?
The numerator and denominator are divided by their greatest common divisor (GCD). 6/8 has a GCD of 2, so it reduces to 3/4.
How do you divide fractions?
Multiply the first fraction by the reciprocal (the flip) of the second. 1/2 ÷ 3/4 = 1/2 × 4/3 = 4/6 = 2/3.
How do you multiply two fractions?
Multiply the numerators together and the denominators together, then simplify. 2/3 × 3/4 = 6/12, which reduces to 1/2.
How do you subtract fractions with different denominators?
Put them over a common denominator first, then subtract the numerators. 3/4 − 1/6 = 9/12 − 2/12 = 7/12.
Why is the answer sometimes shown as a mixed number?
When the result is top-heavy (an improper fraction), it is also written as a whole number plus a proper fraction. 5/4 becomes 1 1/4.
What happens if I enter a denominator of zero?
Dividing by zero is undefined, so the calculator returns a dash. Every denominator you enter must be a non-zero number.
API — use this calculator from code
Call this calculator as a free JSON endpoint — no key required. Send the field values below as query parameters or JSON. Read the full API docs →
Endpoint
GET https://calculator.free/api/v1/fraction/curl
curl "https://calculator.free/api/v1/fraction/?a_num=1&a_den=2&op=add&b_num=1&b_den=3"JavaScript fetch()
const r = await fetch(
"https://calculator.free/api/v1/fraction/?" + new URLSearchParams({
"a_num": "1",
"a_den": "2",
"op": "add",
"b_num": "1",
"b_den": "3"
}));
const data = await r.json();
console.log(data.results);Results are estimates for general guidance only, not financial, medical or tax advice.