Fraction Calculator
Add, subtract, multiply, or divide two fractions. e.g. “What's 3/4 + 2/5?”
Enter your values
Results update as you type. All calculation happens in your browser.
Methodology
Add, subtract, multiply, or divide two fractions. This tool uses a standard, documented formula and runs entirely on your device.
Last reviewed January 2026 · Runs client-side
Adding, subtracting, and simplifying fractions
Fraction arithmetic is easy to slip on, especially when finding a common denominator or simplifying the result. This calculator adds, subtracts, multiplies, and divides two fractions and reduces the answer to its lowest terms.
It also shows the decimal equivalent, so you can move between the two forms without a second calculation.
How to use this calculator
- Enter the numerator and denominator of the first fraction.
- Choose the operation.
- Enter the second fraction and read the simplified result.
What the inputs mean
- Operation
- Add, subtract, multiply, or divide. Addition and subtraction use a common denominator automatically.
- Numerator and denominator
- Whole numbers for each fraction. The denominator cannot be zero.
3/4 + 2/5 becomes 15/20 + 8/20 = 23/20, which is 1.15 as a decimal.
The formula, in plain terms
The fractions are combined over a common denominator (or multiplied directly), then divided by their greatest common divisor to simplify.
Frequently asked questions
Does it always simplify?
Yes. The result is reduced to lowest terms using the greatest common divisor of the numerator and denominator.
Can it handle division?
Yes. Dividing by a fraction multiplies by its reciprocal, which the calculator does automatically.
Last reviewed January 2026. This explainer is general information, not professional advice.