Fraction Difference Calculator
Subtract the second fraction from the first and return a reduced signed fraction.
How to use Fraction Difference Calculator
1. Enter First Fraction, Second Fraction in the stated order. Use the fraction or ratio format shown in the example. 2. Follow nonzero denominator and whole-number requirements where they apply. Keep corresponding quantities on the same unit scale. 3. Select Calculate or press Enter to see difference. 4. Copy result copies the output; Reset clears the inputs and answer.
Why use this tool?
Find an exact fractional gap without decimal-rounding error.
How the calculation works
Difference = first fraction − second fraction = (a × d − c × b)/(b × d). Integer arithmetic and greatest-common-divisor reduction give an exact result. Integer fraction outputs and decimal-ratio comparisons use exact integer arithmetic; numeric input components are bounded as stated. Numeric input magnitudes, including each fraction or ratio component, must not exceed 9,007,199,254,740,991. Mathematical references: https://openstax.org/books/prealgebra-2e/pages/4-key-concepts and https://openstax.org/books/prealgebra-2e/pages/6-5-solve-proportions-and-their-applications.
Example
First Fraction = 3/4 and Second Fraction = 1/2 give 1/4. Reversing them gives −1/4.
Practical tip
This page uses first minus second. Check that order before interpreting the sign.
Frequently asked questions
What does a negative result mean?
The first fraction is smaller than the second. Equal fractions return 0/1. The result is exact for the accepted whole-number fraction inputs.
Can the exact result be larger than the input limit?
Yes. Exact integer fractions can have larger output numerators or denominators after multiplication. Their text remains exact. Floating-point numeric outputs on other maths pages are limited to the supported numeric range.
Does the tool choose units or round my input first?
Enter corresponding measurements in matching units; the maths forms do not convert units automatically. Exact fraction and ratio text is kept for integer arithmetic. Other numeric operations use browser floating-point values and the display precision stated above.