Fraction Calculator
Add, subtract, multiply, divide or compare two fractions or mixed numbers, including negatives. Get the simplified fraction, mixed number, decimal and every step, calculated with exact integer arithmetic.
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About the Fraction Calculator
Fraction Calculator works with two fractions or mixed numbers at a time. Enter an optional whole number, a numerator and a denominator for each, choose add, subtract, multiply, divide or compare, and the calculator shows the result as a simplified fraction, as a mixed number where that helps, and as a decimal, followed by the steps used to get there.
All fraction arithmetic is done with exact whole-number (integer) maths and simplified with the greatest common divisor, so there is no floating-point rounding in the fraction result; only the decimal line is rounded, to 12 decimal places, and it is labelled when it is not exact. Negative values are supported, inputs are limited to 1,000,000,000 per field, and a clear message appears for a zero denominator, division by a zero fraction, or a result too large to handle precisely.
How to use
- Enter the first fraction: an optional whole number, the numerator and the denominator.
- Choose an operation: add, subtract, multiply, divide or compare.
- Enter the second fraction in the same way.
- Click Calculate to see the simplified result, mixed number, decimal and steps.
- Copy the result or download the summary.
Key features
- Addition, subtraction, multiplication, division and comparison.
- Mixed numbers and negative fractions.
- Exact integer arithmetic with GCD simplification.
- Simplified fraction, mixed number and decimal approximation.
- Step-by-step working, including the lowest common denominator.
- Clear errors for zero denominators, division by zero and oversized results.
Best practices
- Put a minus sign on the whole number for negative mixed numbers (−1 1/2), or on the numerator if there is no whole number (−3/4).
- Leave the whole-number box empty for simple fractions.
- Use the steps to check homework or learn the method.
- Prefer the fraction result when you need an exact value; the decimal may be rounded.
- Use Compare to check which of two fractions is larger without converting by hand.
Benefits
- Exact answers with no rounding in the fraction result.
- Shows the working, not just the answer.
- Handles mixed numbers and negatives correctly.
- Private: calculations run in your browser.
Frequently asked questions
How are mixed numbers entered?
Use the whole-number box for the whole part and the numerator and denominator boxes for the fraction, for example 2 and 3/4. The calculator converts it to an improper fraction (11/4) before calculating.
How do negative mixed numbers work?
A minus sign on the whole number applies to the whole value, so −1 1/2 means −(1 + 1/2) = −3/2. With no whole number, put the minus sign on the numerator.
Is the answer exact?
Yes. The fraction result is calculated with exact integer arithmetic and simplified with the greatest common divisor. Only the decimal line can be rounded, and it says so.
Why do I get an error when dividing?
Dividing by a fraction equal to zero is not defined. The calculator also rejects a denominator of zero in either fraction.
How does comparison work?
The calculator cross-multiplies: for a/b and c/d it compares a × d with c × b, which avoids rounding and gives an exact <, > or = result.
Are there limits on the numbers?
Each whole number, numerator and denominator must be at most 1,000,000,000, and results with more than 30 digits are rejected with a precision message.