Calculate the minimum PCB trace width for a given current (or the maximum current for a given width) using the IPC-2221 standard, for external and internal layers. Also shows trace resistance, voltage drop, and power loss.
Trace length (optional)
External layer (top / bottom)
0.300 mm
11.83 mil
Resistance 86.62 mฮฉ
Voltage drop 86.62 mV
Power loss 86.62 mW
Cross-section 16.3 milยฒ
Internal layer
0.781 mm
30.76 mil
Resistance 33.3 mฮฉ
Voltage drop 33.3 mV
Power loss 33.3 mW
Cross-section 42.4 milยฒ
IPC-2221: I = k ยท ฮT0.44 ยท A0.725 (A in milยฒ, k = 0.048 external, 0.024 internal). Internal layers need wider traces because heat dissipates less. IPC-2152 is more accurate for modern boards; treat these results as a conservative starting point.