Fraction Calculator
Add, subtract, multiply, or divide two fractions — reduced automatically.
How to use
- Enter both fractions.
- Choose the operation.
- Click Calculate to see the reduced result and decimal.
Free online math tool.
What Is a Fraction Calculator?
Fractions are where everyday arithmetic gets fiddly: adding 3/4 and 1/2 requires common denominators, dividing flips a fraction upside down, and the answer then needs simplifying. This calculator handles all of it — enter two fractions, choose add, subtract, multiply, or divide, and it returns the result simplified to lowest terms, along with its mixed-number and decimal forms. It is built for homework checks, recipe scaling, workshop measurements, and every other place fractions refuse to stay simple.
The simplification step is where hand calculation most often goes unfinished: 6/8 is a correct sum but not a finished answer. The calculator reduces automatically using the greatest common divisor (GCD) — the largest number that divides both numerator and denominator — turning 36/48 into 3/4 in one step, exactly as a teacher would demand.
How to Use the Fraction Calculator
- Enter the first fraction: numerator in the top box, denominator in the bottom box.
- Choose the operation: add, subtract, multiply, or divide.
- Enter the second fraction the same way.
- Click Calculate to see the simplified result, its mixed-number form, and its decimal equivalent.
The Rules It Applies For You
Addition and subtraction need a common denominator: 3/4 + 1/2 becomes 3/4 + 2/4 = 5/4. Multiplication is direct — numerators multiply, denominators multiply: 3/4 × 1/2 = 3/8. Division inverts the second fraction and then multiplies: 3/4 ÷ 1/2 = 3/4 × 2/1 = 3/2. Results greater than one are also expressed as mixed numbers (5/4 = 1 1/4), which is the form recipes and tape measures actually speak in, and as decimals, which is the form that lets you compare two results at a glance.
Tips for Fraction Work
- For mixed numbers like 2 1/2, convert first: enter it as an improper fraction ((2×2+1)/2 = 5/2), calculate, and read the answer back in the mixed-number form shown.
- Estimating before calculating catches gross errors: if both fractions are under 1, their sum must be under 2 and their product must be smaller than either.
- On a tape measure, think in sixteenths: converting results to decimals and multiplying by 16 locates the nearest sixteenth-inch mark quickly.
How do I add fractions with different denominators?
Find a common denominator — the least common multiple of the two denominators — rewrite both fractions at that size, then add the numerators. For 1/3 + 1/4: the common denominator is 12, giving 4/12 + 3/12 = 7/12. The calculator does all of this internally and then reduces the answer if needed.
Why does dividing by a fraction make the answer bigger?
Because division asks "how many of these fit into that?" Dividing by 1/2 asks how many halves fit — twice as many as the starting number, so 3/4 ÷ 1/2 = 1 1/2. The "flip and multiply" rule is just this logic formalized: dividing by a/b is the same as multiplying by b/a.
What does it mean to simplify a fraction?
Simplifying (or reducing) divides numerator and denominator by their greatest common divisor until nothing larger than 1 divides both. Simplified fractions are easier to picture, compare, and combine further — and they are the required final form in school mathematics. The value never changes; only the representation gets cleaner.
Can this calculator handle negative fractions or whole numbers?
Yes — enter a negative sign on a numerator and the operation rules handle the rest (a negative times a negative gives a positive, and so on). For a whole number, simply use 1 as its denominator: 3 becomes 3/1. Denominators of zero are undefined and cannot be entered meaningfully — no calculator can divide by zero.