How to use the fraction calculator
Enter the first fraction, choose addition, subtraction, multiplication, or division, and enter the second fraction. You can enter ordinary fractions such as 3/4 or mixed numbers such as 1 1/2. The calculator gives the result as a simplified fraction and, when appropriate, as a mixed number.
To reduce a single fraction, switch to the Simplify mode and enter the numerator and denominator. The calculator divides both by their greatest common factor (GCF) to put the fraction in lowest terms.
How fraction arithmetic works
a/b ± c/d = (a×d ± c×b) / (b×d)
a/b × c/d = (a×c) / (b×d)
a/b ÷ c/d = a/b × d/c = (a×d) / (b×c)
Every result is automatically reduced to lowest terms. When a result is larger than 1, both the improper-fraction form (like 15/4) and the equivalent mixed-number form (like 3¾) are shown together.
How to add, subtract, multiply, and divide fractions
Adding fractions
Fractions with the same denominator can be added by adding their numerators and keeping the denominator. For different denominators, first find a common denominator.
For example:
1/2 + 1/3 = 3/6 + 2/6 = 5/6
Subtracting fractions
Subtract fractions using the same common-denominator method. Subtract the numerators while keeping the common denominator.
3/4 - 1/6 = 9/12 - 2/12 = 7/12
Multiplying fractions
Multiply the numerators together and multiply the denominators together. The result can then be reduced to lowest terms.
2/3 × 3/5 = 6/15 = 2/5
Dividing fractions
To divide by a fraction, multiply by its reciprocal. In other words, keep the first fraction, flip the second fraction, and multiply.
2/3 ÷ 4/5 = 2/3 × 5/4 = 10/12 = 5/6
How to simplify a fraction
To simplify a fraction, divide the numerator and denominator by their greatest common factor. Continue until the numerator and denominator have no common factor greater than 1.
For example, to simplify 18/24, the greatest common factor of 18 and 24 is 6:
18 ÷ 6 = 3
24 ÷ 6 = 4
18/24 = 3/4
The fraction 3/4 is in lowest terms because 3 and 4 have no common factor greater than 1. If you need to find the greatest common factor separately, use the GCF & LCM Calculator.
Mixed numbers and improper fractions
A mixed number combines a whole number and a fraction, such as 2 1/3. An improper fraction has a numerator that is greater than or equal to its denominator, such as 7/3. They can represent the same value.
To convert a mixed number to an improper fraction, multiply the whole number by the denominator, add the numerator, and put the result over the original denominator:
2 1/3 = (2 × 3 + 1)/3 = 7/3
To convert an improper fraction back to a mixed number, divide the numerator by the denominator. The quotient is the whole-number part and the remainder becomes the new numerator.
7/3 = 2 1/3
Fractions and decimals
A fraction can also be written as a decimal. To convert a fraction to a decimal, divide the numerator by the denominator. For example:
3/4 = 3 ÷ 4 = 0.75
Use the Fraction to Decimal Calculator when you want to convert one or more fractions into decimal form. To convert a decimal back into a fraction, use the Decimal to Fraction Calculator.
Frequently asked questions
How do you add fractions with different denominators?
Cross-multiply to get a common denominator: a/b + c/d becomes (a×d + c×b) over (b×d), then simplify the result. For example, 1/2 + 1/3 = (1×3 + 1×2)/(2×3) = 5/6.
How do you divide fractions?
Multiply by the reciprocal of the second fraction — flip it upside down, then multiply straight across. 1/2 ÷ 1/4 becomes 1/2 × 4/1 = 2.
How do you simplify a fraction?
Divide the numerator and denominator by their greatest common factor. For example, 18/24 simplifies to 3/4 because both 18 and 24 can be divided by 6. A fraction is fully simplified when the numerator and denominator have no common factor greater than 1.
How do you multiply fractions?
Multiply the numerators together and the denominators together, then simplify the result. For example, 2/3 × 3/5 = 6/15 = 2/5.
How do you subtract fractions?
Find a common denominator, rewrite both fractions using that denominator, and subtract the numerators. For example, 3/4 - 1/6 = 9/12 - 2/12 = 7/12.
What does it mean to simplify a fraction?
Simplifying a fraction means reducing it to its lowest terms without changing its value. Divide the numerator and denominator by their greatest common factor. For example, 12/18 simplifies to 2/3.
Can I use mixed numbers in the calculator?
Yes — enter a whole number in the small box to the left of each fraction. Leave it empty for a plain fraction with no whole-number part.