If I finish a sentence with a bracket should the full stop be inside or outside the bracket? For example, is it .) or ).
Outside the bracket, every time.
In the example you give, you are using parentheses, not brackets. Either way, though, the full stop belongs outside.
Parentheses bookend a word or clause that can be removed from the sentence and it will still make perfect sense; putting the period, question mark, etc. inside leaves you with no indication that the sentence ends, just the parenthetical.
Brackets indicate that (within a quote) someone other than the speaker is inserting a comment, or (within any other text) that someone other than the author is commenting, perhaps an editor or moderator. Either way, you still need a full stop outside those brackets.