Add, subtract, multiply or divide two fractions. The answer is shown fully simplified, as a mixed number where it applies, and as a decimal.
Quick answer: To enter a fraction on a calculator, type the numerator, press the fraction (a b/c) key or the ÷ key, then the denominator — e.g. 3 ÷ 4 for ¾. To turn a fraction into a decimal without a calculator, just divide the top number by the bottom (3 ÷ 4 = 0.75).
Fractions are combined over a common denominator, then reduced by their greatest common divisor.
This fraction calculator does the four basic operations on two fractions and always gives the answer in lowest terms. It handles negative fractions and improper fractions, and shows the result as a mixed number and a decimal so you can use whichever form you need.
How fractions are combined
Add / subtract: a/b ± c/d = (a·d ± c·b) / (b·d) Multiply: a/b × c/d = (a·c) / (b·d) · Divide: a/b ÷ c/d = (a·d) / (b·c) then divide top and bottom by their greatest common divisor.
Worked example
1/2 + 1/3: put both over 6 to get 3/6 + 2/6 = 5/6. It is already in lowest terms, and as a decimal that is 0.8333. For 2/3 × 3/4 = 6/12, which simplifies to 1/2.
Simplifying and mixed numbers
A fraction is in lowest terms when the top and bottom share no common factor other than 1. If the top is larger than the bottom, it is an improper fraction and can be written as a mixed number — a whole part plus a proper fraction, such as 7/2 = 3½.
Frequently asked questions
How do I put a fraction into a calculator?
On a basic calculator, divide the numerator by the denominator (3 ÷ 4). On a scientific calculator, use the fraction key — often marked "a b/c" or a stacked ▢/▢ — pressing it between the top and bottom numbers. On a phone, type it as a division: 3 ÷ 4.
How do I convert a fraction to a decimal without a calculator?
Divide the top number by the bottom using long division. For 3/4, 3 ÷ 4 = 0.75. If the division doesn't end, it either repeats (1/3 = 0.333…) or you round to the places you need.
How do I add fractions with different denominators?
Rewrite them over a common denominator (the product of the two works), add the numerators, then simplify.
How do I divide fractions?
Multiply the first fraction by the reciprocal of the second — flip the second fraction and multiply.
What is a mixed number?
A whole number together with a proper fraction, like 1¾. It is another way of writing an improper fraction.
Does it handle negative fractions?
Yes. Enter a negative numerator (or denominator) and the sign is carried through and shown on the result.
Written by the CalcPine team · Reviewed for accuracy · Last updated 23 July 2026 · Method: common-denominator arithmetic reduced by the greatest common divisor.
