Reference Designer Calculators

PCB Trace Width Calculator

As the current in the PCB traces rises, the wires carrying the current gets hotter. If we keep increasing the current, a point will come where it will be unsafe or undesirable for the temperature to increase. A wider trace will have higher current carrying capacity.

The Calculator calculates the required PCB trace width for a given current.

Following is the formula for calculating the resistance of PCB trace

Width = (Current[Amps]/(k * (Temp_Rise[deg. C])b))(1/c))/ Thickness , in mils


For IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725

For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725

Few obvious Observation

1. The required width increase is directly proportional to the required current.
2. We may increase the copper plate thickness to increase the current carrying capacity or reduce the required width
Enter the values and hit Width Button to calculate the required trace width.

Thanks, Mike Cortopassi, Digital Design Corp.( ) for pointing the error in the displayed formula.

Required Current in Amps
Units mils
Tolerable increase in temperature deg C
Select the Layer    outer inner
  (Required Width ) mils