Transfer gpa and overall gpa difference

So I am confused as to what is the difference between these two. I have only ever calculated my overall gpa at my community college and was wondering how do I determine my UC gpa? Do UCs look at both or just the UC gpa?

UC only looks at UC-transferable. They do not calculate in the other courses.

The easiest way to calculate is to go to assist.org, pick your CCC, then do NOT pick a UC. Instead go down to botttom of the page and click on “UC transferable courses” and then “select by department.” You can search the courses you took to see if they transfer.