RTP (Return To Player) is the theoretical percentage of winnings that a Slot game will pay back to a player over time.
Let's say that you make a hundred bets worth $1 each on a Slot with an RTP of 90%. In this case, you might expect to get back about $90 in winnings. But you should be aware that due to the nature of statistical variances in the RTP percentages, the returns based on staking can vary over game sessions in both directions.
You can check the RTP for all Slots we have on offer. Just start the game you're interested in and go to Game Rules or Help.