How to use this fraction calculator
Add, subtract, multiply or divide two fractions and simplify the exact result. Start with the labeled example values, then replace them with the figures for your problem. Keep units consistent. Results update as you type. If an entry is invalid, the result is cleared and the page explains what needs attention, rather than showing a stale answer.
Formula and calculation method
For addition, a/b + c/d = (ad + bc)/(bd). Subtraction changes the plus sign to minus. Multiplication gives ac/bd. Division gives ad/bc and requires the second fraction to be non-zero. The numerator and denominator are divided by their greatest common factor; a negative sign is kept in the numerator.
Worked example
For 1/2 + 1/3, the numerator is 1 × 3 + 1 × 2 = 5 and the denominator is 2 × 3 = 6, giving 5/6. Multiplying the same fractions gives 1/6. Dividing gives 3/2. The exact simplified fraction is the primary result; the decimal is an approximation.
Assumptions and limitations
Enter integer terms of up to 12 digits. Zero denominators are invalid. This version accepts two fractions rather than mixed-number notation or an entire algebra expression. Convert a mixed number to an improper fraction before entry. Large exact terms may produce a rounded decimal approximation.
Check and keep your result
Check the example by hand before applying the result to your own figures. Download the result to retain the inputs with the output, or use Print for a paper copy. Calculations run locally in your browser and entries are not sent to our server. The website’s advertising services operate separately; see our privacy policy.
Created and calculation-tested by Velour Trends · Updated 8 November 2026. No independent professional review is claimed. Report a calculation issue.