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What Is PCB Current Calculator, its Importance, And How To Use?

The PCB standard of IPC-2221 contains various requirements and specifications for the manufacture and design of circuit boards. Today, there are various web-based calculators that follow this standard. Apart from calculating the annular ring and impedance, it also focuses on the trace width, temperature rise, and trace current. Both standards, IPC-2152 and IPC-2221, include guidelines regarding designing the PCB for thermal tolerance. Both standards have a distinctly detailed debate over the applicability and usage of both standards. 

If you decide to choose the IPC-2221 standard, then don’t be afraid. We have made a very simple and easy-to-use PCB calculator that helps to determine the limits of trace width in a given limit of heat. If you use Altium Designer, you can find these features in the Circuit Board Editor while working on the PCB routing.

Types Of PCB Current Calculators and Trace Width 


The trace width of PCB can be determined through various distinct calculators. All these PCB calculators follow the standard of the PCB industry. These PCB industry standards follow the guidelines for calculations. Both the IPC-2221 and IPC-2152 standards are widely used in commercial and industrial applications. 

1. IPC 2221 PCB Trace Width

The calculator IPC-2221 uses a graph and an equation to calculate the current of the PCB track. The formula stands for I=kΔTbAc.

In this formula, the Visible traces represent the K which has a value of 0.0048, and internal traces also represent the K which has a value of 0.024. ΔT represents the change in temperature in Celsius. The B value equals 0.44, and the C value equals 0.725. Whereas, A represents the area of cross-section.

The IPC-2221 calculator only uses a specific range of all values to calculate the PCB trace width. The range of current falls between 35 and 0 amperes, track width between 10.16 to 0 mm, the width of copper between 3 to 0.5 oz, and the rise in temperature between 100 to 10 oC. It does not give accurate results if the value changes from these specific ranges.

2. IPC 2152 PCB Trace Width

The Calculator IPC-2152 uses an advanced and recent standard type for the calculation. This gives a more precise and accurate calculation of Max capacity of trace current. It uses advanced technical methods. The formula of this calculator does not seem simple as compared to the calculator IPC-2221. To determine the unorganized area of the cross-section, it uses a universal graph.

However, this IPC-2152 calculator uses various types of parameters to create a number of modifiers. Therefore, the parameters include the thickness of the trace for passing, the distance between the tracks and copper planes, as well as the thermal conductivity of the PCB.

What’s In IPC-2221 in Electronics Industry?

An IPC-2221 is a type of standard for the acceptance and qualification of PCBAs and PCBs. The standards demand some requirements and specifications to design a PCB, which ensure the manufacturability, reliability, and safety of a PCB. These standards come in generic standards. At the same time, you can specify a certain type of standard that applies to the PCB used in the whole series of 2220.

The IPC-2221 calculator uses the above formula to calculate the width of the PCB trace, which is needed to keep the level of temperature below a certain range. In simple words, you just have to enter the weight of the copper in the calculator. As a result, it gives you the value of trace width, which is required within the given temperature rise and current. 

Does the IPC-2221 calculator exist in an online system of CAD? Well, yes, the user of Altium Designer can avail of this tool in the tools of routing present in the window of PCB Editor. To analyze the trace width, just select the trace and then expand the information in the NEt Data area present in the Panel of Properties.

PCB Current Calculator: IPC-2221 Formula


The formulas mentioned above have some things to note to find which show precise and accurate results. 

  1. The formula is chart-based.
  2. The formula predicts that the PCB lies at STP in an open environment with air.
  3. The prototypes before using a trace of only thick PCBs and no extra copper planes to disperse heat.
  4. They treat multiple parallel closer traces as one bug trace to pass the current.
  5. If the thinness of the board falls below 30 mils, it recommends to derate it by 15% rather than 10%.
  6. Higher thermal capability substrates have distinct limits of trace and current width than a conventional laminate of epoxy-fiberglass.

This means that the IPC-2221 calculator does not give accurate results when it comes to modern PCBs. In simple words, the value of current capacity changes if you put an additional plane and copper around the trace, and it gives an underestimated value. On the other hand, it gets reversed with a minimum width of trace and gives an overestimated value. Remember these points, as it helps in calculating an accurate trace width.

Because of the nuisance of this standard with modern PCBs, designers and engineers were forced to create an advanced standard that gives higher efficiency, accuracy, and specificity. And then comes the IPC-2152 standard.

IPC-2221 Vs. IPC2152: Which is the Best to Use?

All online calculators have some limitations. The calculator IPC-2221 also falls in this category. It’s the fact that the IPC-2221 calculator gives an overestimated value of minimum trace width. Therefore, the standard IPC-2152 calculator expands the data to add numerous nomographs which determine the current limits, temperature rise, and trace width.

Currents a PCB Trace Carry and its Importance


The PCB trace current capacity limitation is one of the main problems which arise in various electronic projects. In many home projects, the value never exceeds the maximum limit, which seems better.

The calculator helps greatly in determining the current capacity of PCB trace yet gives a hard time in handling the charts. As the max PCB trace, the current capacity is linked with the operational temperature and width. 

Importance of Using the PCB Current Calculator Trace Width

The current calculator of PCB trace is an easy-to-use tool. It is divided into Output and Input sections which makes it easy to put data and obtain the results. The fields in this calculator include the following:

  1. The Internal and External trace location according to the substrate of PCB.
  2. The width of the trace represents the distance.
  3. The thickness of the trace represents the horizontal length of the PCB trace.
  4. The Max temperature rise represents the maximum value of a difference between the ambient temperature and PCB trace.

However, in advanced features:

  1. The surrounding temperature.
  2. The trace length from start to end.
  3. The Max PCB traces current capacity.
  4. The trace cross-sectional area.
  5. The temperature of trace while operation.
  6. The trace resistance at Max PCB traces current capacity.
  7. The drop of voltage for the max current and calculated resistance value.
  8. The dissipation of power at the max rate of current capacity.

Guidelines and Tips for Using the PCB Current Calculator 

The current that flows through the track and the specification of design determines the trace width of the PCB. However, it follows a specific rule. The minimum value of the traceroute ranges from 10 mm/A. This goes well for a 1.0 oz/ft2 thickness of copper.

The calculation of trace width is a complex process. That is why it requires some rules to understand for calculating the trace width of PCB. The circuit works well on max current with ambient temperature, the thickness of the trace, and the trace measurement unit. These values depict the input range of trace width.

When you add these values inside the calculator of trace width, it gives back some output values. This output value represents the PCB trace width. The datasheet shows all the figures of input. It does not work with guess figures. All PCB requires this information to calculate the trace width.

The calculator does not work well and gives no output if the input value is wrong. You may also need a magnifying glass so that you can see the exact values on the PCB.

Confirming the Efficient Trace Width with PCB Calculator 

· Standard Track Width

First, decide the track size for the PCB in your design. Too thin, narrow, and close tracks lead to short circuits. At the same time, too much spacing between the tracks must need some restriction on the track number. In such scenarios, incorporate extra plane layers in the PCB to make sure the routing of the PCB.

· Circuit Pad Shapes

The libraries of components typically possess PCB libraries for the schematic and footprint of different electrical components. Although, it depends on the process of PCB manufacturing. Therefore, you have to select the process of manufacturing before beginning the design process. This way, you can select the appropriate size of pads and later on incorporate it over the CAD system of PCB. 

· Track the Size of Lines

PCBs Possess a thin track of line which limits the carrying capacity of current. That is why we must consider the size of the trace for any route that carries a power current instead of lesser signal levels.

· Dimensions Of Hole & Pad

It’s important to decide on the pad and the hole dimension once you begin the design of the PCB. It may vary according to various situations. Sometimes, the ratio of pad-to-hole falls to 1:8. Sometimes, it measures when the pad is bigger than the hole. The manufacturers of PCBs have their own set of standards according to the usage of the application. The ratio gets more crucial as the size of the pads, and the hole decreases.

Factors to Think about When Developing PCB Trace Width 

The trace width of a PCB directly affects the functionality of a PCB in many ways. However, we have a few factors to take into account while determining the value of trace width.

· Signal Integrity & Electrical Performance

The majority of PCB digital routing possesses the default trace width value, yet some may need distinct sizes. For instance, the steady impedance net of traces needs the evaluation of trace width on the basis of the stack up of PCB layer consideration. 

In most cases, analog routing requires the PCB trace width according to the circuitry usage. Well, in some cases, one can also decrease the default width of traces in compact spaces. You only need to make sure that it will not extend the surface of the PCB. 

· PCB Fabrication

Wider traces fabricate easily on the PCB. The process of etching traces leaves a greater effect on the isolated and long traces. That is why make sure to create wider traces. For example, a trace of 20 mils has a greater current tolerance capacity than a trace of 3 mils. Moreover, the weight of the copper determines the width of the traces in a PCB.

· Power & Grounding Routing

The trace of ground and power routing should have enough space to lead to a greater amount of amperes. As thin traces get hot easily, it leads to burning. Moreover, the internal layers of the PCB must have wider and broader traces so that heat disperses easily. Furthermore, the power traces on the outer layers of the PCB have better exposure to the outer air, which helps the traces to chill.

Therefore, outer sheets don’t require wide and broader traces. Traces incorporated in the circuitry of the power supply must have wide but short traces so that the current flows evenly. Make sure for greater spacing between the traces, which also helps in greater current flow.


A Circuit board trace calculator helps you to evaluate various aspects of trace. This includes trace temperature, dissipation of power, voltage drop, resistance, and max current capacity. You can also evaluate the width of the trace following the current capacity it holds while using the calculator. This article explains in detail the PCB calculator of trace width. I hope this information helps you in your endeavor to trace the width of the PCB calculator.




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