Fraction Calculator
Add, subtract, multiply, or divide two fractions. Enter a numerator and denominator for each fraction and get an instantly simplified result.
1/2 + 1/3 = 5/6
Recommended Settings
Pro Tips
- •The result is automatically simplified to its lowest terms using the greatest common divisor
- •Dividing by a fraction with a numerator of 0 is undefined, just like dividing by zero
- •A negative denominator is automatically normalized so the negative sign appears on the numerator instead
- •The mixed number view is useful when the result is an improper fraction (numerator larger than denominator)
Most Popular
Most users work with addition and subtraction for combining measurements or recipe quantities
When to Use This Tool
Check fraction arithmetic homework or work through practice problems step by step.
Combine or adjust fractional ingredient amounts when scaling a recipe up or down.
Add or subtract fractional measurements, like combining lengths given in fractions of an inch.
See exactly how a fraction operation is simplified to its lowest terms.
How It Works
Read the numerator and denominator for each fraction
Apply the standard formula for the selected operation - common denominators for addition and subtraction, direct multiplication for multiply, and cross-multiplication for divide
Simplify the resulting fraction by dividing both the numerator and denominator by their greatest common divisor
Display the simplified fraction alongside its decimal and mixed-number equivalents
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side JavaScript arithmetic for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
How are fractions added or subtracted?
The fractions are converted to a common denominator by cross-multiplying, then the numerators are added or subtracted. The result is simplified back down using the greatest common divisor.
How is a fraction simplified?
The greatest common divisor (GCD) of the numerator and denominator is calculated, and both are divided by it. For example, 4/8 simplifies to 1/2 because their GCD is 4.
Why does it say the result is undefined?
This happens when a denominator is zero, or when dividing by a fraction whose numerator is zero - both cases involve division by zero, which has no defined result.
Is my data sent to a server?
No. All calculations happen instantly in your browser using JavaScript. Nothing you enter is transmitted anywhere.
Can I enter negative fractions?
Yes. Enter a negative sign on either the numerator or denominator, and the result will be normalized so the sign appears on the numerator.