The general equation of a hyperbola is \( \frac{x^2}{a^2} - \frac{y^2}{b^2} = 1 \). The eccentricity \( e \) of a hyperbola is given by:
\[
e = \sqrt{1 + \frac{b^2}{a^2}}
\]
Comparing the given equation with the standard form, we find that the eccentricity is \( \sqrt{2} \).