PCB Trace Width Clearance

Printed Circuit Boards (PCBs) have a wire-like structure made from copper, which is responsible for establishing an electrical connection between two or more points. This copper structure is referred to as a trace. The traces help in carrying current from one point to the other on a PCB. Traces are also sometimes referred to as tracks, because they form tracks for carrying current on a printed circuit board. Both these terms are synonyms and can be used interchangeably. We can design circuit boards with different PCB trace widths and clearances.

Calculating PCB Trace Width

The rise in the amount of current flowing through a PCB traces heats up the wires carrying current, as they get heated. If the amount of current rises continuously, at one point, it would be unsafe for the circuit as well as the board. Thus, trace width is increased to increase the current carrying capacity. This prevents the wires carrying current from getting heated.

To calculate the trace width, first the area needs to be computed. The formula for calculating the area is:

Area [mils2] = (Current [Amps]/ (k * (Temp_Rise [deg. C]) b))(1/c)


  • For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725
  • For IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725

Now that the area is calculated, you can calculate the trace width by the following formula: Width [mils] = Area [mils2]/ (Thickness [oz]* 1.378 [mils/oz])

Inner Layers (Trace Width/Clearance) Outer Layers (Trace Width/Clearance)
0.5oz: 4/ 4mil 1/ 3oz- Hoz: 4/ 4mil
1oz: 5/ 5mil 1oz: 5/ 5mil
2oz: 5/ 7mil 2oz: 5/ 7mil
3oz: 7/ 8mil 3oz: 7/ 8mil
4oz: 10/ 10mil 4oz: 10/ 10mil
5oz 12/ 12mil 5oz: 12/ 12mil
6oz/ 15/ 12mil 6oz: 15/ 12mil

At Twisted Traces, we have a vast experience in manufacturing printed circuit boards with different trace widths and clearances. For the past three decades, we have been providing high-quality products and extending prompt services to all our customers. This has helped us to gain trust, and build a large base of happy, satisfied, and loyal customers. We are very keen to provide only high-quality circuit boards. Besides this, we are proud to provide you with the fastest turnaround times in the industry. All the printed circuit boards that we provide are available at reasonable and competitive prices. Would you like to know more about the trace width and clearance of PCBs that we provide? Then, get in touch with us at the earliest.

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