DocomintFraction Calculator
Simplify a fraction or add, subtract, multiply, and divide two fractions, with the steps shown.
What is a Fraction Calculator?
Built for the two most common fraction tasks: reducing an ugly fraction like 18/24 down to its simplest form, or combining two fractions with different denominators — the step students most often get stuck on, since it needs a shared denominator before the numerators can be added or subtracted at all.
How to use the Fraction Calculator
- Choose simplify, or an operation between two fractions
- Enter the numerator and denominator for each fraction
- The result — simplified — appears instantly, calculated on your device
Formula
Simplify: a/b → (a÷GCD)/(b÷GCD) | Add/Subtract: a/b ± c/d = (a×d ± c×b)/(b×d) | Multiply: (a×c)/(b×d) | Divide: (a×d)/(b×c)
Adding or subtracting first cross-multiplies to a common denominator (b×d); multiplying is straight across; dividing flips the second fraction and multiplies. Every result is simplified with the GCD before being returned.
Example
Adding 1/2 and 1/3 needs a common denominator of 6 first — 3/6 + 2/6 — before the numerators combine to 5/6. Enter 1, 2, 1, 3 in Add mode and it returns 5/6 directly, skipping the manual common-denominator step.
Common mistakes
- Adding numerators and denominators straight across (1/2 + 1/3 is not 2/5) instead of finding a common denominator first.
- Forgetting to simplify the result after adding or subtracting, leaving an answer like 6/8 instead of 3/4.
- Flipping the wrong fraction when dividing — it's always the second fraction that gets inverted, not the first.
- Entering a denominator of 0, which is undefined rather than just a very large or small number.
Frequently asked questions
How do you simplify a fraction?
Divide both the numerator and denominator by their greatest common divisor (GCD). 18/24 has a GCD of 6, so dividing both by 6 gives the simplified fraction 3/4.
How do you add fractions with different denominators?
Convert both fractions to a common denominator first — usually the least common multiple of the two denominators — then add the numerators. 1/2 + 1/3 becomes 3/6 + 2/6 = 5/6.
Can I enter negative numbers or improper fractions?
Yes — negative numerators/denominators and improper fractions (numerator larger than denominator, like 9/4) both work; the result isn't forced into a mixed number.
How do I convert a fraction to a decimal?
Divide the numerator by the denominator — 3/4 is 0.75. This tool works in fraction form throughout rather than showing a decimal equivalent alongside the result.
Is my numbers uploaded anywhere?
No — Fraction Calculator runs entirely in your browser using JavaScript/WebAssembly. Your numbers is never sent to a server.