Controlled Impedance Calculator
Hitting a target characteristic impedance — for a high-speed signal, a differential pair, or anything a fab house needs to hold to spec — means solving IPC-2141's microstrip or stripline geometry equations. This calculator handles both surface microstrip and symmetric stripline, solving for trace width from a target impedance or checking the impedance a given geometry actually produces.
Controlled Impedance Trace
Surface microstrip (IPC-2141)
Show your work
Geometry
Width for target Z₀
10.93 mil
Width for target Z₀
0.2777 mm
Check an existing width
Resulting Z₀
47.06 Ω
Propagation delay
139.5 ps/inch
These closed-form IPC-2141 equations are accurate to a few percent for typical FR-4 stackups. Always confirm the final width with your fabricator's impedance-controlled stackup before release.