The Return to Player (RTP) percentage is a measure of the percentage of stakes a slot machine gives back to players over time. Essentially, it indicates the potential payout you could receive for playing. For example, if a slot machine has an RTP of 95%, theoretically, for every $100 wagered, the machine would pay out $95 over its lifetime. Different denominations on a machine can have different RTP percentages, with higher denominations often offering a higher RTP.