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PCB Trace Resistance Calculator
Calculate PCB trace resistance, voltage drop, power loss, and current density from trace length, width, copper thickness, temperature, and current. This tool is intended for PCB power rail checks, sensor wiring, low-voltage drop analysis, and layout review.
Input Parameters
Results
For high-current traces, use this result together with a PCB trace width or temperature-rise calculator and the board manufacturer's copper tolerance.
Equations Used
Trace Area: A = width × copper thickness
Copper Resistance at 20°C: R20 = ρ × L / A, where ρ ≈ 1.724×10⁻⁸ Ω·m for copper.
Temperature Correction: R = R20 × [1 + 0.00393 × (T - 20°C)]
Voltage Drop: Vdrop = I × R
Power Loss: P = I² × R
Frequently Asked Questions (FAQ)
Q1: What does PCB trace resistance affect?
Trace resistance affects voltage drop, heat generation, regulator margin, current sensing accuracy, and low-voltage power distribution.
Q2: Why does copper temperature matter?
Copper resistance increases as temperature rises, so a hot PCB trace has more voltage drop than the same trace at room temperature.
Q3: Should I use one-way length or round-trip length?
This tool calculates the resistance of the single trace entered. For a supply-and-return path, calculate both paths or enter the combined equivalent length.
Q4: Does this replace IPC current capacity rules?
No. It estimates electrical resistance and loss. Temperature rise, copper spreading, layer position, airflow, and board stackup require separate analysis.
Q5: Is 1 oz copper exactly 35 µm?
35 µm is a common nominal value. Finished copper thickness can vary with base copper, plating, and manufacturing tolerance.
