Embodiments of methods, apparatus, and systems for extracting impedance for a circuit design are disclosed herein. Some of the disclosed embodiments are computationally efficient and can accurately compute the frequency-dependent impedance of VLSI interconnects and/or intentional inductors in the presence of multi-layer conductive substrates. In certain embodiments, the resulting accuracy and CPU time reduction are a result of a Green's function approach with the correct quasi-static limit, a modified discrete complex image approximation to the Green's function, and a continuous dipole expansion to evaluate the magnetic vector potential at the distances relevant to VLSI interconnects and intentional inductors.