Fraction Calculator
Compute the sum, difference, product or quotient of two fractions, simplified to lowest terms with the decimal equivalent.
Example
Add 1/2 and 1/3:
1/2 + 1/3
= (1x3 + 1x2) / (2x3)
= 5/6
Decimal = 0.83333333
How it works
Enter the numerator and denominator of each fraction and pick an operation. The result is reduced by the greatest common divisor and shown as both a fraction and a decimal.
Good to know
This Fraction Calculator takes two fractions, applies one of four operations (add, subtract, multiply, or divide), and returns a single answer reduced to lowest terms. Alongside the simplified fraction it shows the decimal value, the original expression you entered, and the answer rewritten as a mixed number. It's handy for students checking homework, anyone scaling a recipe or measurement, and DIY or woodworking tasks where dimensions land on sixteenths and thirty-seconds of an inch.
Reach for it whenever combining fractions by hand is error-prone, for example adding 3/8 and 5/16, or dividing a quantity like 2/3 by 1/4. Because everything runs in your browser, you can use it offline once the page has loaded, and no inputs are sent anywhere. The fields accept negative and improper numerators, so it works for signed arithmetic and top-heavy fractions too.
Reading the output is straightforward, but watch a few details. The main figure is already in lowest terms, so 6/12 will display as 1/2. If the result equals a whole number the denominator disappears (you'll see 5, not 5/1), and the decimal is rounded to eight places, which is why 5/6 shows as 0.83333333 rather than a repeating value. The "Mixed number" row is the same value split into a whole part plus a proper fraction, which is often easier to picture for measurements.
- A denominator of zero is rejected, and dividing by a fraction whose numerator is zero returns "Undefined" rather than a number.
- The decimal is a rounded approximation, so treat the fraction as the exact answer when precision matters.
Frequently asked questions
How is the result simplified?
The numerator and denominator are divided by their greatest common divisor (GCD), reducing the fraction to its lowest terms. For example, 6/12 becomes 1/2.
What happens when I divide fractions?
Dividing by a fraction multiplies by its reciprocal: (a/b) / (c/d) = (a*d) / (b*c). If the second numerator is 0, the result is undefined and an error message is shown.
Is my data uploaded anywhere?
No — this calculator runs entirely in your browser; nothing is uploaded.
Is it free?
Yes, completely free with no sign-up and no limits.
People also ask
How do you add two fractions with different denominators?
Convert both to a common denominator, then add the numerators. The fastest reliable common denominator is the product of the two denominators: a/b + c/d = (a*d + c*b) / (b*d), which you then reduce to lowest terms.
What is a mixed number versus an improper fraction?
An improper fraction has a numerator larger than or equal to its denominator, such as 5/3. A mixed number expresses the same value as a whole number plus a proper fraction, so 5/3 becomes 1 2/3.
How do you convert a fraction to a decimal?
Divide the numerator by the denominator. For example, 3/4 equals 3 divided by 4, which is 0.75; some fractions like 1/3 produce repeating decimals that have to be rounded.
Can a fraction have a negative numerator or denominator?
Yes. A negative sign can sit on the numerator, the denominator, or in front of the whole fraction, and they represent the same value; conventionally the sign is moved to the numerator, so -1/2, 1/-2, and -(1/2) are equal.
Why is dividing by zero undefined?
Division asks how many times one quantity fits into another, and there is no number you can multiply by zero to get a nonzero result. Because no answer exists, division by zero, including by a fraction equal to zero, is left undefined.
How do you multiply fractions?
Multiply the numerators together and the denominators together, then simplify: (a/b) * (c/d) = (a*c) / (b*d). Unlike addition, no common denominator is needed.
What does reducing a fraction to lowest terms mean?
It means dividing both the numerator and denominator by their greatest common divisor so no smaller equivalent fraction exists. For instance, 8/12 reduces to 2/3 because both share a factor of 4.
Are repeating decimals exact when shown by a calculator?
No. Calculators display a rounded, finite number of digits, so a value like 1/3 appears as 0.33333333 rather than the true repeating decimal. The fraction form remains the exact representation.
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