PCB Impedance Calculator
Estimate microstrip, embedded microstrip, and stripline impedance, effective dielectric constant, capacitance, and delay.
Characteristic impedance–
Effective Er–
Capacitance–
Propagation delay–
About PCB impedance estimates
Microstrip uses Hammerstad-style approximations; symmetric stripline uses a common closed-form estimate. Embedded microstrip nudges the effective dielectric constant upward for the solder-mask / cover layer. Effective Er also sets the capacitance per length and the propagation delay.
Closed-form equations are useful for early stackup planning. Confirm final controlled-impedance dimensions with your fabricator or a field solver that includes real copper shape and solder mask.