Games of chance and payout ratio (RTP)

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Payout ratio (also known as expected return, payout percentage or RTP – return to player) of a game of chance is the long-term statistical rate of total money won divided by the total money staked. The opposite of the payout ratio is the house edge. The house edge is calculated as 100% minus payout ratio. If the payout ratio is 95% then the house edge is 100% – 95% = 5%.

Let's take a closer look at payout ratios of some of the most popular games of chance.
  • Payout ratio of roulette
In European Roulette, the probability of winning when betting on the black color is 18 (number of the black numbers) divided by 37 (number of all numbers, don't forget the zero). The payout is 2 times the bet.

The payout ratio of roulette is then 2 * 18 / 37 = 0.973 = 97.3%. House edge is then 100% – 97.3% = 2.7%. The roulette game is set to have the same RTP for all kinds of bets (color, number, etc.).

American roulette has a much worse RTP and one type of bet with RTP different from all of the other bets.

As blackjack rules may vary from casino to casino, it's obvious that RTP may differ as well. But generally, a game of blackjack played by a player utilizing the basic blackjack strategy gives an expected RTP of around 99.5%.

In live and online blackjack the expected RTP changes as the dealer deals cards from the deck. The RTP in this case is usually between 95% and 102%, depending on which cards are left in the "shoe". This is exploited by card counters – players which estimate the actual RTP of the blackjack deck and try to bet high if the RTP is over 100%, to make a long-term profit. On the other hand, casinos also have means to detect such card-counters and prevent them from playing further.

  • Payout percentage of slot machines
The RTP of slots is usually between 92% and 99%. Payout percentage of slot machines is determined by the symbols on the virtual reels, by payout table, and by other specific rules applied to each particular game.