How to Use the Subtracting Fractions Calculator

Same two-fraction input as the Adding Fractions calculator, subtracting instead — order matters here, so the first fraction entered is the one being subtracted from.

a/b − c/d = (ad − bc) / (bd)

Same cross-multiplication as addition, subtraction in the numerator instead. 3/4 − 1/3 works out to (9 − 4)/12, or 5/12. If the second fraction outweighs the first, the result just comes out negative — nothing unusual, the same as subtracting a bigger whole number from a smaller one.

This Subtracting Fractions Calculator simplifies the answer automatically, dividing both numerator and denominator by their greatest common factor until nothing further reduces.