The term Return To Player or RTP is used to describe the game's theoretical payout percentage, or how much of the money you bet will be paid back over time. For example, if a particular game has an RTP of 95%, it means that players can expect to receive back €95 in winnings for every €100 they wager, at least theoretically.
However, players need to take two things into consideration. Firstly, no matter how accurate the RTP of a particular game is, it only represents the average return over extended periods of time. If a player's betting session is quite short, the actual RTP may differ significantly from the statistics published by the online casino
Therefore, in roulette, the RTP represents the average return over many spins through extended periods of time. In other words, the more spins the wheel takes, the more accurate the actual roulette return information becomes.
Another thing to remember is that RTP does not work as an indicator of how often you win at roulette (or any other game). The RTP published by a given online casino is the same for all the types of bets you can place on roulette. But if a player only places even wagers, such as Black/Red or Even/Even, they will certainly receive payouts more often than a player, who bets on single numbers.
According to European and American roulette rules, the player loses every time the ball lands on zero. And it is well known that American roulette has two zeros (a single and a double zero). So the odds of winning in American roulette are 1 in 38, which results in an RTP of 94.74%. European roulette, on the other hand, has only one zero, which means that the odds of winning in this version of the roulette are 1 in 37 resulting in an RTP of 97.3 %.