In electrical engineering, **admittance** *Y* is the inverse or reciprocal *Y* = *Z*^{−1} = 1/*Z* of impedance *Z*. Just as impedance is complex resistance, and conductance *G* is the inverse *G* = 1/*R* of resistance *R*, admittance is also **complex conductance**.

Likewise, admittance is made up of a real part (the conductance), and the imaginary part called susceptance *B*, shown by the equation *Y* = *G* + *jB*.