PCB Trace Width Calculator (IPC-2221)
Required trace width for a given current, copper weight, and temperature rise.
Values
Result
Width ≈ 1.26 mm (49.6 mil)
IPC-2221 trace sizing
The IPC-2221 standard relates current capacity to cross-section area: I = k · ΔT0.44 · A0.725, with k = 0.048 for external traces and 0.024 for internal layers (A in mil², ΔT in °C). The calculator solves for the required area and divides by the copper thickness to get the minimum trace width.
Use this as a starting point, then add margin — connectors, bends and nearby heat sources all reduce current capacity.