PCB Trace Resistance Calculator

How to Use PCB Trace Resistance Calculator

Enter the trace length, width, and copper thickness. Choose units that match the drawing or PCB stackup.
Enable temperature compensation when the trace will run above or below 20 °C.
Enter current if you also want voltage drop and power loss for that trace.
Use the milliohm result for short power paths; use resistance per meter when comparing geometry choices independent of length.

Formula & Theory - PCB Trace Resistance Calculator

R = ρ × L / A
A = width × thickness
RT = R20 × [1 + α × (T - 20)]
Copper α ≈ 0.00393 / °C

DC trace resistance follows the conductor formula: longer traces increase resistance, while wider or thicker copper lowers resistance.

Copper resistance rises with temperature. The temperature compensation applies a linear correction around 20 °C using the standard copper temperature coefficient.

The calculation assumes a rectangular copper cross section. Real etched traces may be trapezoidal, and plating, copper roughness, and frequency-dependent skin effect are not included.

Use Cases for PCB Trace Resistance Calculator

Checking whether a power trace causes too much voltage drop.
Estimating I²R heating in LED, motor, or battery paths.
Comparing 1 oz and 2 oz copper for a DC rail.
Creating quick resistance budgets for low-ohm current-sense layouts.

Frequently asked questions about PCB Trace Resistance Calculator

What does PCB Trace Resistance Calculator calculate?

Calculate PCB copper trace DC resistance, resistance per length, voltage drop, and I²R power loss with temperature correction.

Can I use the result as a final design value?

Use it as a fast calculation or planning estimate. Engineering, finance, safety, and production decisions should still be checked against the relevant standard, data sheet, or professional review.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.