Fraction Calculator
Add, subtract, multiply, or divide two fractions.
How this works
Adding or subtracting fractions with different denominators means finding a common denominator first -- this calculator does that by cross-multiplying, then simplifies the result down to its lowest terms by dividing both the numerator and denominator by their greatest common factor. Multiplying and dividing don’t need a common denominator at all: multiply straight across, or (for division) flip the second fraction and multiply.
The result shows three equivalent forms: simplest form (the fraction reduced as far as it goes), a mixed number (a whole number plus a leftover fraction, once the numerator is bigger than the denominator), and the decimal equivalent. All three represent the exact same value -- which one is most useful just depends on what you’re using it for.
Frequently asked questions
How do you add fractions with different denominators?
Cross-multiply to put both fractions over a common denominator first: multiply the first fraction’s numerator and denominator by the second fraction’s denominator, and do the same in reverse for the second fraction. Once both fractions share a denominator, you can add or subtract the numerators directly.
What does “simplest form” mean?
A fraction is in simplest form when its numerator and denominator share no common factor other than 1 -- dividing both by their greatest common factor (GCF) gets you there. For example, 6/8 simplifies to 3/4, since 2 is the largest number that divides evenly into both.
What’s the difference between a mixed number and an improper fraction?
An improper fraction has a numerator larger than its denominator, like 7/2. A mixed number writes that same value as a whole number plus a leftover fraction instead -- 7/2 becomes 3 1/2. They’re two different ways of writing the exact same value.
Can I enter a whole number instead of a fraction?
Yes -- enter the whole number as the numerator and 1 as the denominator (5 becomes 5/1). Any whole number is just a fraction with a denominator of 1, so the math works exactly the same way.