Enter the overall length of the SMT Pad and the quantity of thermal connecting traces into the PCB Thermal Relief Width Calculator. The calculator will evaluate the PCB Thermal Relief Width. 

PCB Thermal Relief Width Formula

The following two example problems outline the steps and information needed to calculate the PCB Thermal Relief Width.

TW = (X*.60)/Y

Variables:

  • TW is the PCB Thermal Relief Width ((trace width))
  • X is the overall length of the SMT Pad 
  • Y is the quantity of thermal connecting traces 

To calculate the PCB thermal relief, multiply the overall length of the SMT pad by .60, then divide by the quantity of thermal connecting traces.

How to Calculate PCB Thermal Relief Width?

The following steps outline how to calculate the PCB Thermal Relief Width.

  1. First, determine the overall length of the SMT Pad. 
  2. Next, determine the quantity of thermal connecting traces. 
  3. Next, gather the formula from above = TW = (X*.60)/Y.
  4. Finally, calculate the PCB Thermal Relief Width.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

overall length of the SMT Pad = 4

quantity of thermal connecting traces = 3

TW = (X*.60)/Y = ?