An online casino's 'return-to-player percentage' (or 'RTP%') refers to the portion of the total amount you've wagered that is, on average, returned to you. For example, for every $100 wagered at an online casino with an RTP of 96%, you would expect to win at least $96 back. Knowing the RTP% of a specific online casino or casino game is important because it can help you mitigate losses and increase your chances of winning.