Enter the design pressure (kPa), the outside diameter (mm), and the design factor into the Spade Thickness Calculator. The calculator will evaluate the Spade Thickness. 

Spade Thickness Formula

The following formula is used to calculate the Spade Thickness. 

ST = P*D / (2*F*S)


  • ST is the Spade Thickness (mm)
  • P is the design pressure (kPa) 
  • D is the outside diameter (mm) 
  • F is the design factor 
  • S is the yield strength (kPa)

To calculate the spade thickness, multiply the design pressure by the outside diameter, then divide by the product of 2 times the design factor times the yield strength.

How to Calculate Spade Thickness?

The following steps outline how to calculate the Spade Thickness.

  1. First, determine the design pressure (kPa).
  2. Next, determine the outside diameter (mm). 
  3. Next, determine the design factor. 
  4. Next, gather the formula from above = ST = P*D / (2*F*S).
  5. Finally, calculate the Spade Thickness.
  6. 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.

design pressure (kPa) = 7900

outside diameter (mm) = 250

design factor = .89

ST = P*D / (2*F*S) =  ?