PCB Trace Current Calculator

Estimate PCB trace width or current capacity, resistance, voltage drop, and power using the IPC-2221 approximation.

Required width–

Cross-section–

Resistance–

Voltage drop / power–

About trace current estimates

I = k × ΔT^0.44 × A^0.725

A is the copper cross-section in square mils; k is 0.048 for external layers and 0.024 for internal layers (IPC-2221). Switch the mode to size a trace for a target current, or to find the current a given width can carry for the chosen temperature rise.

These are first-pass estimates. Real board temperature depends on copper pours, airflow, layer stackup, solder mask, and nearby heat sources — validate high-current designs thermally.