➗ Fraction Calculator
Add, subtract, multiply, or divide fractions — automatically simplified
Calculate With Fractions
Fraction A
Fraction B
Fraction Calculator Guide
How Fraction Operations Work
To add or subtract fractions, they need a common denominator first — this calculator does that automatically by cross-multiplying. To multiply fractions, multiply the numerators together and the denominators together. To divide, multiply the first fraction by the reciprocal (flip) of the second.
| Operation | Formula | Example |
|---|---|---|
| Addition | a/b + c/d = (ad + bc)/bd | 1/2 + 1/3 = 5/6 |
| Subtraction | a/b − c/d = (ad − bc)/bd | 3/4 − 1/4 = 1/2 |
| Multiplication | a/b × c/d = ac/bd | 2/3 × 3/4 = 1/2 |
| Division | a/b ÷ c/d = ad/bc | 1/2 ÷ 1/4 = 2 |
What Are Mixed Numbers?
A mixed number combines a whole number and a fraction, like 1½. This calculator converts mixed numbers to improper fractions internally (1½ becomes 3/2) before doing the math, then converts the answer back to a mixed number for display when possible.
Frequently Asked Questions
How do I simplify a fraction?
Divide both the numerator and denominator by their greatest common divisor (GCD). For example, 8/12 has a GCD of 4, so it simplifies to 2/3. This calculator simplifies every result automatically.
Can I use negative fractions?
Yes — enter a negative number in the numerator or whole-number field and the calculator will handle the sign correctly through any operation.
Why do I need a common denominator to add fractions?
A fraction represents parts of a whole, and the denominator defines how big each "part" is. You can't directly add 1/2 and 1/3 because halves and thirds are different sizes — converting both to sixths (3/6 and 2/6) makes the parts the same size so they can be added.
How do I convert a fraction to a decimal?
Divide the numerator by the denominator. For example, 3/4 = 3 ÷ 4 = 0.75. This calculator shows the decimal equivalent alongside every result.
What if my denominator is 0?
Division by zero is undefined in mathematics — a denominator of 0 isn't a valid fraction. This calculator will flag that as an invalid entry.