Asymmetric Stripline Impedance Calculator

  1. Fill in the relative permittivity of the dielectric and the trace width, thickness and distance to each plane.
  2. Select the Zo button to calculate the characteristic impedance of the trace.

You can also choose to fill in the desired characteristic impedance and leave one of the trace parameters blank. Selecting the button next to the blank field will calculate the missing parameter. Equations used to make these calculations are provided at the bottom of this page.

Units for T, the trace thickness:
mils  Oz

H mils
Calculation Results:
Zc ohms
Lo nH/in
Co pF/in
Tpd ns/in


Zo Equation: IPC-D-317A (Eq. 5.38a)

The equation for Co in IPC-D-317A (Eq. 5.38b) is inconsistent with the equation for Zo (Eq. 5.38a). The equation used here can be derived by multiplying the propagation delay by the characteristic impedance.

Asymmetric Stripline

Are there distributed capacitive loads on this trace?
No  Yes

If there are distributed loads, please provide the average length of the traces attachingthe loads and the average load capacitance.

Trace Length  inches
Total Load pF

formula for asymmetric stripline structure