PCB analysis / Free calculator

Via resistance & parallel vias

Calculate the DC resistance of plated through-hole barrels and an ideal parallel-via group.

01 Your inputs

Calculated on your device. Inputs are not transmitted or stored.

02 Your result

Enter your values and select Calculate.

Inside a plated via

Side section

Plated via through a circuit boardA hollow hole passes through the board. Copper plating lines both sides of the hole. The finished hole diameter d spans the inner copper surfaces, t measures one copper wall, and L spans the board thickness. Arrows along the copper show current through the barrel.

Barrel end view

Copper cross-section of one via barrelThe copper area A is a ring around the open hole, with inner diameter d and radial plating thickness t. The hole contains no conducting copper.Ad

The copper ring is the conducting area A.

CopperBoard material
d
Finished hole diameter
t
Plating thickness of one wall
L
Board thickness / barrel length
Current flows along the copper barrel. For n identical parallel vias, each carries I/n. Surface pads are shown for orientation; their resistance is excluded. Symbolic model; not to scale.

The method

A=πt(d+t)R=ρLnA

A worked example

For a 0.3 mm finished hole, 25 µm plating, 1.6 mm board, and four equal vias at 20 °C, total resistance is approximately 270.2 µΩ. At 1 A total, each via carries 0.25 A.

Assumptions & limits

Identical cylindrical barrels and equal current sharing. Finished hole diameter describes the inner copper surface. Via count must be a positive safe integer. Excludes spreading resistance, pads, thermal limits, inductance, blind/buried geometry, and uneven plating. Temperature scope matches the trace model.

Calculation source: Extracted from PCBA Workbench v1.2.0.

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