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PCB Trace Current Calculator

Created by Álvaro Díez
Reviewed by Dominik Czernia, PhD and Jack Bowater
Last updated: Jun 05, 2023

With the PCB trace current calculator, you can compute the current capacity of your PCB trace in a breeze. How much current a PCB trace can carry limits your design, so you can use this tool to verify if everything is going to be okay without having to return to the drawing board in the future.

If you are interested in other PCB trace properties, check the PCB trace width calculator and the PCB trace resistance calculator. There is the PCB impedance calculator, too! We've got you covered.

How much current can a PCB trace carry, and why does it matters?

The limitations of the current capacity on a PCB trace are one of the many constraints we face when dealing with an electronic project. In many home projects, you will never hit the maximum values allowed by your trace, but, as they say, better safe than sorry.

Chart representing current vs width vs temperature for a PCB
Current vs width vs temperature graph for PCB.

Using a PCB trace current capacity calculator is always a good idea, but charts like the one above can also be handy. As you can see, the maximum amperage capacity of a PCB trace is a function of its width and its operational temperature.

Such charts are a great place to start, but what if you want to know what the actual current of your trace will be? Then you use Omni Calculator's PCB trace current calculator!

How to use the PCB trace current calculator?

The PCB trace current calculator is a straightforward tool to use. We conveniently divided it into Input and Output sections so you can easily obtain the current capacity from your input data. The fields in the calculator are:

  • Location of the trace with respect to the PCB substrate: Internal or External;
  • Trace width - The distance across the trace;
  • Trace thickness - The vertical height of the trace in the typical (textbook) PCB orientation; and
  • Maximum desired temperature rise - The maximum allowed difference in temperature between the PCB trace and the ambient temperature.

And, in the Advanced mode:

  • Ambient temperature of the environment;
  • Length of the trace from beginning to end;
  • Max current - the current capacity of the PCB trace;
  • Cross-sectional area of the trace;
  • Trace temperature during operation;
  • Resistance of the trace at maximum current capacity;
  • Voltage drop for the calculated resistance and max current values, calculated using Ohm's Law (see the voltage drop calculator for more information); and
  • Power dissipation at maximum current capacity.

As with all Omni Calculators, you can fill in the data as you see fit; no need to follow the Input and Output recommendations. Additionally, the PCB trace current calculator has a smart feature that will compute and populate any field as soon as you introduce enough input data.

More than just a PCB trace current capacity calculator

This calculator is much more than a PCB trace current capacity calculator. On top of computing how much current can a PCB trace carry, it tells you the voltage drop of the trace at such a current, the power dissipation, the resistance, and the cross-section.

Álvaro Díez
The trace is...
side view of the pcb trace
Trace width
Trace thickness
Max. desired temperature rise
Max. current
Cross section
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