PCB Trace Width Calculator

This sizes a printed circuit board trace with the IPC-2221B conductor charts, fitted as A = (I / (k x dT^0.44))^(1/0.725). Give the current, the temperature rise you will accept, whether the trace sits on an outer or inner layer and the copper weight, and it returns the width in mils and millimetres with the cross-section, resistance, voltage drop and power over the length you enter. A second mode runs the same curve backwards from a width you already have. IPC-2152 superseded this chart in 2009 and measures differently, so treat the figure as a starting point rather than a thermal analysis.

Calculator Type
Trace Dimensions In
One mil is a thousandth of an inch, so 20 mils is 0.508 mm. This sets how the width and the length below are read, and how the answers come back. Copper weight stays in ounces per square foot either way, because that is how laminate is sold everywhere.

The narrowest trace that carries a given current without heating more than you allow, plus what it will drop and dissipate over its length.

The steady current the trace carries. The IPC chart runs to 35 A.
How much hotter than the board around it the trace may run. 10 C is the usual conservative choice, 20 C is common, and the IPC chart stops at 100 C.
Only used for resistance, voltage drop and power. Leave it blank for a one inch trace if you only want the width.
Only used to put copper resistance at the right temperature. It does not change the width the chart asks for.
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Trace Dimensions In
One mil is a thousandth of an inch, so 20 mils is 0.508 mm. This sets how the width and the length below are read, and how the answers come back. Copper weight stays in ounces per square foot either way, because that is how laminate is sold everywhere.

The other direction: a trace width you already have, and the current it will take at a temperature rise you are willing to accept.

Mils, or millimetres if you switched above. One mil is a thousandth of an inch, so 20 mils is 0.508 mm.
How much hotter than the board around it the trace may run. 10 C is the usual conservative choice, 20 C is common, and the IPC chart stops at 100 C.
Only used for resistance, voltage drop and power. Leave it blank for a one inch trace if you only want the width.
Only used to put copper resistance at the right temperature. It does not change the width the chart asks for.
Widget
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