PCB impedance calculator

This tool computes the characteristic impedance Z0 of PCB traces for microstrip and stripline configurations. It accepts inputs such as trace width (W), substrate height (h), copper thickness (t), and dielectric constant (ε_r), and then applies standard closed-form equations to produce Z0. Conceptually, the process begins by normalizing geometry through the W/h ratio, then selecting the appropriate regime and applying ε_eff calculations for microstrip. The result informs trace width choices to meet target impedance, aiding signal integrity planning and routing decisions. The tool benefits hardware engineers, RF designers, and students who need repeatable estimates during schematic-to-layout handoffs or feasibility checks for high-speed designs. Its unique value lies in combining widely used microstrip and stripline formulas into a single quick-access calculator, reducing the need to switch between references. Core features include automated regime selection, optional ε_eff reporting, and tolerance folding for stack-up variations. Use cases include designing 50 Ω microstrip routes on FR4, or 100 Ω differential pairs on controlled-impedance boards, where rapid Z0 checks accelerate iteration and communication with fabrication partners.
These capabilities are intended for preliminary design and verification, not full-wave simulation. The tool assumes uniform substrate properties and neglects via effects, anisotropy, and frequency-dependent conductor losses, which may become relevant at very high frequencies.