Calculation of open area: round holes, triangular pitch
![](/files/design/gfx/calculation/type_1.gif)
Calculation of open area: round holes, rectangular pitch
![](/files/design/gfx/calculation/type_2.gif)
Calculation of open area: square holes, rectangular pitch
![](/files/design/gfx/calculation/type_6.gif)
Calculation of open area: square holes, staggered pitch
![](/files/design/gfx/calculation/type_3.gif)
Calculation of open area: slot holes, staggered pitch
![](/files/design/gfx/calculation/type_4.gif)
Calculation of open area: rectangular holes, staggered pitch
![](/files/design/gfx/calculation/type_5.gif)