Fraction Calculator
Two fractions in, one answer out — in lowest terms, as a mixed number and as a decimal, with every step of the working shown. Nothing is uploaded.
The first box of each pair is the whole number of a mixed number. Leave it at zero for an ordinary fraction.
How to use it
- Type the two fractions. The first box in each group is the whole number, so 2½ is entered as 2, then 1, then 2.
- Pick the operation in the middle dropdown.
- Read the answer, then open the working box below it if you need to show your steps rather than just the result.
How the sums work
Adding and subtracting need a common denominator, and the reliable way to get one is to multiply each fraction by the other one’s bottom number. Three quarters plus one sixth becomes eighteen twenty-fourths plus four twenty-fourths, which is twenty-two twenty-fourths, and that simplifies to eleven twelfths.
Multiplying is the easy one: tops together, bottoms together. Dividing is the same thing with the second fraction turned upside down, which is why textbooks say invert and multiply. Every answer here is reduced to lowest terms afterwards by dividing both halves by their greatest common divisor.
Mixed numbers and improper fractions
A mixed number like 2½ is converted to the improper fraction 5/2 before anything else happens, because arithmetic on mixed numbers is awkward and error-prone. The answer is given back both ways, so you can use whichever form the question asked for.
Negatives work as you would expect. A minus on the whole number makes the whole quantity negative, so −2½ is −5/2, not −2 plus a half. If you want only the fraction to be negative, leave the whole box at zero and put the minus on the numerator.
Frequently asked questions
How do you add fractions with different denominators?
Give them the same denominator first. The quickest way is to multiply each fraction by the other one's denominator, so three quarters plus one sixth becomes eighteen twenty-fourths plus four twenty-fourths, which is twenty-two twenty-fourths, and that simplifies to eleven twelfths. The working box on this page shows each of those steps.
What does simplifying to lowest terms mean?
It means dividing the top and the bottom by the largest number that goes into both, which is called the greatest common divisor. Twenty-two twenty-fourths has a greatest common divisor of two, so it becomes eleven twelfths. The fraction is worth exactly the same, it is just written with smaller numbers.
Can it handle mixed numbers and negative fractions?
Yes to both. Put the whole part in the first box of each fraction, and the calculator converts it to an improper fraction before doing anything else. A minus sign on the whole number makes the entire fraction negative, which is how a mixed number is normally read.
Is anything I type sent anywhere?
No. The arithmetic happens in JavaScript inside your own browser. Nothing is uploaded and nothing is saved - close the tab and it is gone.