How to transfer non graded subjects to gpa?
While this was ultimately cleared up in the comments, for future readers:

In the US, the term for a class which counts as credit but has no grade attached is "Pass-Fail". You either get credit towards the degree, or you don't, but there is no grade attached. In general (I'm aware of no exceptions to this in the US, at least), pass-fail courses do not count for purposes of GPA, so there's no way to convert a credit-only class to GPA - it's just a class you received credit for.

One situation which is more complicated is if you have a class that provides something like a "narrative grade", which I'm told exists but have no personal experience with, and it doesn't have a direct correlate to GPA systems in the US. If you encounter that you'll simply need to speak with the institution to which you are applying and they'll have to make the determination as to how to handle such coursework.