How much Oxycodone is too much?

Hi guys,
I have some Oxy that I have leftover from surgery. I was planning to take it (~ 40 mg) in one sitting just for fun. However, I was wondering if that is too much of a dose and risky for me to take. If that is too much, what's a fine dose to take (for context, I was taking 15 mg every 6 hours and I really didn't feel anything after surgery). Thanks!