L-Network Matching Calculator
Match a source resistance to a load with two reactive components, and read off the Q, the bandwidth and the part values.
If the load is a different multiple of the source …
An L-network uses one series reactance and one shunt reactance to transform a resistance. The shunt element goes across the larger resistance and the series element in line with the smaller one. With Q = √(Rhigh / Rlow − 1), the series reactance is Q × Rlow and the shunt reactance is Rhigh / Q. At frequency f, L = X / (2πf) and C = 1 / (2πfX). The low-pass form uses a series inductor and a shunt capacitor; the high-pass form swaps them. Because the resistance ratio fixes Q, the match is inherently narrowband: the loaded bandwidth below is approximately f / Q, and the network only matches at its design frequency. Real parts also carry their own losses, tolerances and self-resonance, so measure the finished network. Everything is computed in your browser: nothing is stored or sent anywhere.