Multiple RTP configurations are built into every slot
Game developers do not create a slot machine that pays out at a single RTP. Instead, they create slot machines with several RTP settings. There are typically three to five different RTP settings within a slot machine.
For most slot machines, the RTP settings used are 94%, 96%, and 97%. Developers make these available to all casinos. Casinos select which one they wish to use.
This is a practice that is common in the industry. The information is made available in the terms and conditions of each casino. However, almost no player ever reads the terms and conditions.
How the selection process works
Developer builds multiple configurations
Each of these RTP settings is a separate configuration within the slot machine. The paytable can be different, the features can be different, or both can be different to produce that specific RTP percentage.
Casino negotiates and signs a licence
Casinos enter into an agreement with developers of slot machines. One of the terms of that agreement is the RTP settings that the developer will make available to that casino.
Casino activates the chosen setting
Through their game management backend, casinos select which configuration to run. Most casinos select one instead of trying to run multiple settings simultaneously.
The selected RTP is applied to every spin
All players at that casino will play on that configuration from that point forward. However, the casino has the power to change the settings.
Is this legal?
Yes - in regulated markets around the world. Gambling regulators such as the UK Gambling Commission allow slot machines to have different configurations of RTP settings within the range that the manufacturer has specified. If a casino selects a slot game, the live RTP must be disclosed to players upon request.
The legal minimum RTP settings in regulated markets are lower than the RTP settings offered by most slot games (70% is the legal minimum in the UK). Casinos are allowed to use any RTP configurations that they choose that fall within the range that the game developer has specified.
Regulators do not require casinos to use the highest RTP settings. Casinos are not required to make the RTP settings prominent within their slot game listings. However, in the game itself, the live RTP must be available somewhere for players to find.
How large are the gaps?
For every slot game that we track at 10 different casinos, we verify the live RTP settings for every slot game by loading the game and reviewing the in-game help screen. We have found some gaps between maximum and minimum RTP settings within casinos.
For example, for the slot game Le Bandit by Hacksaw Gaming, one of the best casinos in the market runs the slot machine at an RTP of 96.34%. However, at one of the worst casinos in the market, the RTP is only 92.17%.
The 4.17 percentage point gap indicates that if a player puts £100 in one casino, they will lose on average £4.17 less at the casino that pays out at 96.34% compared to the casino that pays out at 92.17%.
This gap is not unique to the slot game Le Bandit. Most popular slot games have a gap between their best and worst RTP settings ranging between 2% and 3%. See our full breakdown of the biggest RTP settings differences that we have found within slot games.
Why casinos do not advertise lower settings
Casinos want to use the lower RTP settings because that increases their margins on slot games. Casinos do not want to reveal this to players - as it would encourage them to migrate to casinos with higher RTP settings.
Slot game developers always know the exact RTP settings of the slot games that they make and publish. However, almost no slot game players know that they can find this information out themselves.
How to check the actual RTP at any casino
Our database contains information from 10 different casinos across all of the slot games that we have tracked. For every slot game we track, we publish information on the RTP settings that each of the 10 casinos run for that game. See which casinos consistently run the highest settings and which ones run the lowest.
Can casinos change the RTP after you start playing?
In regulated markets, changing the RTP settings during a slot game session is not permitted. When a player begins to play a slot game, that casino's RTP setting will apply to that player for that game session. However, the casino is required to provide notice to players before changing the RTP settings within a game session.
Casinos can and do change the RTP settings that they use for their slot games over time. A casino that uses an RTP of 96% for a slot game today might switch to 94% next month. This is why we periodically check all of the slot game RTP settings within our database.