Current carrying capacity PCB trace | Calculator | Table | Current-carrying capacity | PCBs

Estimating Trace Heating

This tool serves as a rough estimate for trace heating under current load. The calculation is based on the IPC-2221 ("Generic Standard on Printed Board Design"), which received an update in 1968. In this update, the values for current load capacity were reduced by approximately 40%, as practical applications often showed higher heat development than calculated. The IPC-2152 ("Standard for Determining Current Carrying Capacity in Printed Board Design") later revisited this topic and highlighted that parallel-running traces, in particular, influence each other’s heat development to such an extent that isolated consideration seems impractical. An explanation of the IPC-2152 can be found here: “The Value of IPC-2152 by Michael R. Jouppi” https://www.ipc.org/system/files/technical_resource/E7%26S22_03.pdf.

It should therefore be reiterated that the tool below provides only a rough estimate of the expected trace heating. It is recommended to conduct your own measurements in practice after prototype production.

How to use the trace heating calculator:

First, you need to enter information regarding the number of layers and the assumed copper thickness. Then, you can choose which of the three variables will be calculated as unknown, i.e., which two values are given:

• Current
• Trace width
• Temperature rise

Please note that the temperature difference must always be added to the ambient temperature. This refers solely to the heat generated by the current in the trace.

Tool - Track Heating

Project name:

PCB type:

Single sideDouble sideMultilayer

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Copper thickness

8 12 18 35 55 70 105 140 210 300 400 µm

Calculation of

Temperature difference Current Track width

Track width

mm

Current

A

Temperature difference

°C

Create chart Print results

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*Despite careful assessment there can no responsibility be taken for the correctness of any results. The commercial use and forwarding of created diagrams is permitted when referencing copy rights.

Example calculation for trace width depending on current-carrying capacity:

You want the track to heat up by a maximum of 50°C, with a current of 3A.

Select "track width" to determine it as the unknown. Type in the value "50" for temperature difference and "3" for current. Click create chart. The chart shows how to adjust temperature or current in case the calculated track width is not suitable. In case you realize that your track width is restricted in width you may choose "temeprature difference" as the unknown to see how much it will heat up.

In some cases you may also opt for an increase in copper thickness to allow more current through the trace at a certain heating. In this case, please refer to the minimum track width allowed for each copper thickness. For printed circuits from LeitOn these minimum track widths are listed under "technology".