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PCB Trace Impedance Calculator

Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries.

Select a Configuration

microstrip trace
Microstrip Trace
Embedded microstrip trace
Embedded Microstrip Trace
Stripline Trace
Stripline Trace
Dual Stripline Trace
Dual Stripline Trace
blank space

Geometric Parameter Definitions

W blank pace trace width
T trace thickness
H (/H1) height of trace or dielectric above return plane
C distance between the differential stripline pair
εr relative permittivity of the dielectric

Electrical Parameter Definitions

Z0 blank pace characteristic impedance
Zc effective characteristic impedance including the capacitance of distributed loads
Tpd propagation delay
L0 inductance per unit length
C0 capacitance per unit length


The source for formulas used in this calculator (except where otherwise noted) is the Design Guide for Electronic Packaging Utilizing High-Speed Techniques (4th Working Draft, IPC-2251, February 2001.

THESE FORMULAS ARE APPROXIMATIONS! They should not be used when a high degree of accuracy is required.

This transmission line calculator was based on a concept developed by Douglas Brooks of UltraCAD Design, Inc.