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PCB trace width calculator: what is it? How to use it?


Did you know you need to set up a PCB trace width calculator to avoid damaging your PCB? Did you realize that trace width determines the amount of current you carry? Hope this article can help you find the trace width of your PCB using the PCB trace width calculator.

What’s the definition of PCB trace width?

Whats-the-definition-of-PCB-trace-widthWe’ll start by talking about traces. A PCB copper trace is a thin line of conductive metal used for carrying electrical signals and power throughout an electronic device. It consists of two parts: a conductor and a dielectric. A conductor is any substance that conducts electricity, whereas a dielectric is anything that doesn’t conduct electricity.

The width of the copper trace is what we call the PCB trace width.

How does the PCB trace width calculator work?

The PCB trace width calculator calculates the total cost of a project based on the material used, the number of layers, and the thickness of each layer. You can use the Trace Length option to specify the length of the traces on the board. This value is measured in inches. If you don’t know what the trace length is, just enter “1”.

Let’s walk you through an example case of how the tool works.
First, we will select the type of calculation (Internal/External), for which we are performing the calculations.

1.Internal: Calculate the impedance of traces within the board itself.
2.External: Calculate the impedance between boards.
3.Both internal and external: Calculate both types of impedances.
4.All layers: Calculate the impedance for all layers.
5.Select the layer(s): You can choose one or multiple layers.

How to use PCB trace width calculator?

The PCB trace width calculator is quite easy to use. All you have to do is enter the following information into the calculator:

●Select the location of the board trace (internal/external):
●Input the trace thickness (in mils), the allowable current (in amps), and the allowable temp increase (in degrees).
●Get the results ( PCB Trace Width and Cross Section Area).
●Want more? Try Advanced mode.
●You can find out how wide the traces are and what the cross-sectional area is.

How far apart should PCB traces be?


Trace width refers to the distance between adjacent copper lines. The width of a PCB trace is measured in millimeters (thousandths of an inch). A typical board has traces ranging from 0.1mm to 1.0mm wide. However, some boards may be wider, depending on the application. For example, a 0.5 mm trace could contain 50 µm of copper.

The width of the trace determines where it sits within the board. A wider trace sits closer to the edge of the board while a narrower trace sits closer to the center.

If you want to know what size traces to use, we recommend looking up the datasheet for your specific part.

How do you select a trace width?

According to the experience of most manufacturers,the minimum width for traces set is at 6 mils or 152 microns. However, they usually allow a certain degree of variation, so we often use 10-12 mils or 254-304 microns.

How is PCB trace width calculated?

When calculating the width of a PCB track, there are several variables to consider. These include the number of layers used, the type of material being used, whether copper or aluminum and the size of the pads. In addition, there are some factors that affect the calculation such as the distance between tracks, the spacing between components, and the length of the traces.

The equation for calculating the width of a trace is:
●W is the PCB trace width in thousandths of an inch (thousandths),
●A is the cross-sectional area in square millimeters,
●t is the trace thickness in ounces per foot squared, and
●n is the number of layers used.

Why do we need a PCB trace width calculator?


Trace width is a vital parameter for those who do PCB design. Calculating the correct trace width allows engineers to ensure that the traces are wide enough to carry the required amount of current without causing damage to the board itself.

This calculation requires accurate information about the trace width.
Just entering some parameters, the PCB trace calculator helps us calculate trace width quickly and easily. You simply enter the desired values into the calculator and press the button labeled “Calculate.” A graph appears showing the calculated trace width against the actual trace width.

The trace calculator works best when used with a PCB design software program. However, many programs do not include a trace calculator function. If you don’t use a PCB design software package, just search “PCB trace width calculator”, then you can find several free online tools that provide trace width calculations.

Factors when using the PCB trace width calculator

When calculating PCB trace width, you need to prepare several factors including:
●Copper thickness
●Trace current
●Temperature rise
Factors-when-using-the-PCB-trace-width-calculatorCopper thickness
PCB copper thickness is generally divided into 1OZ (35um), 2OZ (70um), 3OZ (105um). Generally, the double-sided board is 1oz, the inner layer of the multi-layer board is generally 1/2oz 1/3oz, and the outer layer is 1oz 1/2oz 1/3oz, and the copper thickness of the power supply board is required to be higher.

Trace current
The current capability of the trace (how far current will flow through it).The wider the PCB trace, the greater the current carrying capacity. But trace width is not linearly related to current carrying capacity. Assuming that under the same conditions, the 10MIL trace can withstand 1A, but the 50MIL trace cannot withstand 5A current.

Temperature rise
Temperature rise refers to the temperature of the trace when the current is conducting and not conducting. In other words, simply subtract the operating temperature from the higher operating temperature to get the temperature rise.

What’s the formula of the PCB trace width calculator?

For the equations, you just need to use the formula below:
W is PCB trace width in thousandth of an inch (thousands)
A is a Cross-sectional area in square millimeters (square millimeter)
t is the Thickness of the copper in ounces per foot squared (ounces)
n is the Number of layers used (layers)

So if you have a 4-layer board, you would use this formula:
4 * W * t / n A
If you want to find out how much current a given trace width can carry, you can use this formula:
I A * t / W
This means that the current through a trace depends on three factors: its width, the thickness of the copper, and the number of layers used in the board.
What's-the-formula-of-the-PCB-trace-width-calculatorYou can also use the following equation to find the maximum allowable temperature rise:
T max I A * t / W + T ambient
T max is the Maximum allowable temperature rise in degrees Celsius
I Current flowing through the trace
A is the Area of the trace
W is the Width of the trace
t is the Copper thickness
T is the Ambient Temperature of the environment

Where can you download the PCB trace width calculator?

When we search on Google, there will be many entries that allow us to calculate and download. Here we provide you with several methods, you only need to click directly.
Bittele Electronics
These are just a few of the many places where you can download the PCB trace width calculator. If you need more options, you can always check online.


When it comes to PCB design, the limitation imposed by the current capacity of PCB traces is critical. While the IPC-2221 General Design Guidelines are a good starting point, the PCB Trace Width Calculator provides accurate values that can be used in board design and can help us understand the exact PCB trace width.



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