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Microstrip Trace Impedance Calculator

Estimate a microstrip trace's impedance, effective permittivity, delay and guided wavelength from its geometry and laminate.

the copper trace as drawn
dielectric thickness between trace and ground plane
applies to trace width and substrate height
εr of the laminate; FR-4 is about 4.4
GHz; used only for the guided wavelength
Enter the trace geometry to estimate impedance and delay.

Uses the Hammerstad and Jensen closed-form microstrip equations for a zero-thickness trace over a ground plane, with no solder mask or plating. Copper thickness lowers impedance and the effect grows on thin traces, so check the result against your fabricator's stackup and a field solver. The impedance is a low-frequency value; the frequency input only sets the guided wavelength. Everything runs in your browser with no storage, uploads or network access.