TheCircuitDogPCB & Layout
PCB Trace Resistance Calculator
Estimate the DC copper resistance, voltage drop and resistive heating along a straight PCB trace.
Enter the values above and select Calculate result.
Formula
R = ρ × length / (width × thickness), ρCu ≈ 1.724 × 10⁻⁸ Ω·m
Worked example
A 100 mm trace, 0.5 mm wide with 35 µm copper, has approximately 0.099 Ω at 20°C.
Engineering notes
Not an ampacity or temperature-rise calculation. IPC-2152 guidance, adjacent planes, vias, connectors, airflow, ambient and copper-temperature coefficient must be considered.
Always compare calculated values with the actual component datasheet, tolerance stack-up, operating temperature and circuit conditions before applying them to hardware.