The inductance of two parallel conductors can be computed. It is assumed that one of the conductors is the return path for the other wire.
The inductance for the two wire inductance might be useful in measuring the inductance for a signal and ground on a ribbon cable. The inputs to this calculator are length distance between the two conductors and diameter of the wire. These two signals make a complete loop.
The inductance of the loop created with the two wires.
L_{wires}\approx \frac{\mu _{o}\mu _{r}}{\pi}\cosh^{-1}\left ( \frac{s}jokdpubpsir \right )\cdot L
where
s>>d