Smith Chart Calculator Tools for Amateur Radio
Keith Greiner
Updated May 20, 2026
This site includes Smith Chart instructions and calculators for L-networks. The links on this page take you to the calculators.
The charts use an exact binomial calculation to solve the problem of finding inductor (L) and capacitor (C) values that will match your measured device to a 50-ohm load in the primary calculator, and other impedances that are shown below. Although the charts are not guaranteed to provide the correct, perfect, an effort has been made to make them as correct as possible. Hopefully the tools will help explain how the Smith Chart calculatons work for L-networks. For a definitive source, see your NanoVNA tool.
When using these calculators, you enter the frequency in Hz plus the impedance in the variables; "R" for resistance and "jX" for reactance values. The calculator tool will return the values of inductance and capacitance and the configuration needed to make an L-network that matches your measured device with a 50-ohm load.
The returned values may be used to construct an L-network to match your amateur radio transmitter to a feed line or antenna. The text commentary has information about how to select component values and design an L-network.
Details and instructions in the linked commentary pages.
The calculator tools on this site require a laptop or desktop and Javascript capability
This site is still under construction, so expect changes.
Links:
Application of the Smith Chart
How to use the Smith Chart tool and an MFJ 259D
Smith Chart for a 300-ohm load
Smith Chart with a variable ZL load resistance
Transmission Lines and Velocity Factor
(c) 2026