Return to player (RTP)
The percentage of total bets a game is designed to pay back to players over a very large number of rounds.
Return to player (RTP) is a long-run average. A slot with 96% RTP is designed to pay back $96 for every $100 wagered across millions of spins. It says nothing reliable about one session.
Why it matters
RTP is the mirror image of the house edge: 96% RTP means a 4% house edge. Higher RTP means lower expected losses over time.
Variable RTP
Many slot providers release the same game in several RTP versions, for example 96%, 94% and 92%, and the casino chooses which to offer. The game can look identical. Check the RTP figure in the game's information or help screen at the casino you are using, not on the provider's website.
Worked example
Wagering $1,000 on a 96% RTP game has an expected loss of $40. The same $1,000 on a 92% RTP version has an expected loss of $80, double the cost for the same entertainment.
RTP and provably fair games
For provably fair originals such as dice or limbo, RTP comes directly from the payout formula and can be calculated exactly from the published scheme.