Equation for calculating o-ring compression

[Spoolx]

For whatever reason this equation is slipping by me, I don't want to use a calculator though because I am building a spreadsheet.

Can someone please tell me the equation to calculate o-ring compression?

Thanks

 

[Baluncore]

O-rings are used in many different situations. You will need to be more specific about your application.

An O-ring usually seals because of the fluid pressure difference holding the ring against a wall, not because it is compressed.