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How To Use Trace Width Calculator(Fundamentals)

PCB Trace Width Calculator
Minimum Trace Width

Internal Layers

Minimum Trace Width

External Layers in Air


Calculation of appropriate trace width calculator sizes for current-carrying is an essential requirement of circuit board development. Common materials used for PCB tracks layout are copper and aluminum. It can offer a slight resistance when current flows through them.


Trace Width Calculator1


The resistance of a conductor at room temperature depends on three factors: the conductivity of the material, effective length, and the cross-sectional area of the conductor.


Trace Width Calculator–Content


The dc resistance at room temperature with track’s length and cross-sectional area is related by using the following formula:




Where R = Resistance of the conductor (Ω)


ρ = conductivity of conductor (Ω/m)


l= length of the conductor (m)


A = effective cross-sectional area of the conductor (m2)


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Trace Width Calculator2


Fig. 1:- Track width and height (Thickness of copper sheet) over the base material


Fig. 1 shows the common structure of a PCB laminate and width and height relationship of the copper foil.


This relationship is for dc resistance calculation of the track without considering the copper on another layer.


The thickness of a track over a laminated sheet ranges from 17µm to 70µm unless specified otherwise.


The resistance relations show that the resistance is directly proportional to the length of the track, i.e., the longer the route, the higher the opposition, and vice versa.


Trace Width Calculator3


The crosses sectional area is related to the width and height of the conductor. The manufacturer fixes the conductor thickness, and the width is the parameter controlled and varied by the PCB designer or manufacturer.


The track cross-sectional is 


The A = cross-sectional area in (m2)


W = width of the track laid on the PCB


T = Height of the conductor, i.e., copper sheet thickness


These are the DC resistance parameters for a conductor. The voltage drop across a track due to dc resistance is:


Changes the track resistance significantly. This IR drop entirely causes heat dissipation. A Trace Width Calculator available online, offline in the form of excel sheets, or built-in design tool determines.


The width of the conductor at room temperature and elevated temperatures. The chart shows the same things, i.e., the cross-sectional area or thickness of the conductor, current, and temperature rise as in fig. 2.


Trace Width Calculator1.png
Trace Width Calculator4


Fig. 2:- Screenshot of PCB trace width calculator with temperature compensation


PS: For example, the IRDrop analysis tool built into allegro signal integrity tools analyzes the analysis.


Trace Width Calculator5


The width calculation, temperature analysis, and current density in the respective layout design. Track width vs. amperage charts is available easily. But calculators which accompany the temperature effect have better results, particularly in signal integrity analysis.

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Emma Lu
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