punctuation - Where does the period go when using parentheses?

Where should the period go when using parentheses? For example:

In sentence one, I use this example (which has a parenthesis at the end.)

Should the period be inside, or outside of the parentheses? What about if the entire sentence is a parenthetical (as below)?

(Where does the terminal punctuation go here?)

Is there a hard and fast rule?

Answer

The best rule of thumb for punctuating in and around parenthetical remarks is that the sentence should be valid if you remove the parentheses and everything inside them.

Here I have an example (with a parenthetical remark).

Here is the same example (with the same remark, even.)

Removing the entire parenthetical remark from the first sentence still leaves me with a valid structure, while removing it from the second leaves me lacking any terminal punctuation; thus the first is correct.