PCB Trace Width Calculator
Calculate the minimum PCB trace width for a given current using IPC-2221 guidelines.
A
°C
oz
Trace Width (external)
53.8 mils
Trace Width (mm)1.37 mm
Cross-Section Area74.2 mils²
Trace Width (external) vs Current
PCB Trace Width (IPC-2221)
Formula
Area = (I / (k x dT^0.44))^(1/0.725)
Width = Area / Thickness
For external layers k = 0.048. Copper thickness at 1 oz = 1.378 mils. This is for external (outer) layers; internal layers need wider traces due to less cooling.
Example Calculation
3 A current, 10C rise, 1 oz copper.
- 01Thickness = 1 x 1.378 = 1.378 mils
- 02Area = (3 / (0.048 x 10^0.44))^(1/0.725) = ~79.6 mils^2
- 03Width = 79.6 / 1.378 = ~57.8 mils = ~1.47 mm
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