A return to player (RTP) percentage, or the average amount of money returned to players over time, is programmed into each machine. A machinrummy guide apke with a 95 percent RTP, for example, will typically pay out $95 for every $100 wagered. Remember that this is an average over the long run, and that any given player may see short-term results that differ from this number. The degree of volatility in slot machines also varies.