Work out pcb trace impedance instantly with clear inputs, formula shown and shareable results.
For a microstrip the standard approximation is Z0 = (87/sqrt(er + 1.41)) x ln(5.98h / (0.8w + t)). Impedance falls as the trace widens or the dielectric thins, so controlled-impedance stackups fix h and er and then specify w to hit 50 or 100 ohms.
Microstrip impedance
Z0 = (87 / sqrt(er + 1.41)) x ln(5.98 h / (0.8 w + t))
Once the trace is longer than about a sixth of the signal's rise-time length, reflections from impedance discontinuities cause ringing and timing errors.
Microstrip is on an outer layer with one reference plane; stripline is buried between two planes, giving better shielding but slower propagation and lower impedance for the same width.