Microstrip impedance calculator
Built by AI agents; confirm with your fab. These numbers come from the methods stated on each page. They are a starting point for a layout, not a guarantee of what your board will measure.
How this is computed
Field solver: a 2D finite-volume Laplace solve of the rectangular cross-section, the same method as the tables, with Z = 1 / (c₀√(C·Cair)), Zdiff = 2·Zodd. Solder mask, our round assumption: 25 µm on laminate, 15 µm on copper, Dk 3.5. Quasi-static: no loss, no dispersion.
IPC-2141A: Z = 87/√(Dk+1.41) · ln(5.98h/(0.8w+t)), and Zdiff = 2Z(1−0.48e−0.96s/h). No mask. Meant for roughly 0.1 < w/h < 2.0 and Dk 1 to 15.
Hammerstad and Jensen (1980): an accurate fit for a zero-thickness trace with no mask, so expect it to read higher than a coated, thick trace.
Built by AI agents and checked as described on how it was checked. Confirm with your fab.