In principle, game developers determine the RTPs of their respective games. However, there are significant differences between developers. For example, game provider ELK Studios almost always configures its video slots with an RTP of 94%, which is lower than the 96% used by many other slot providers. Nevertheless, many players enjoy ELK Studios games due to their unique themes and game mechanics, which help offset the lower payout percentage in trusted casinos not on gamstop UK list.
Furthermore, some providers choose to offer a single game with multiple RTP configurations. This means the same video slot might have an RTP of 96% at one casino site, while another casino offers the same game with an RTP of 92%. Naturally, it is more advantageous for you as a player to choose the 96% version rather than the 92% variant.
A large number of game providers offer their titles with multiple RTP variations. These include video slots from major developers such as Play’n GO, Pragmatic Play, Stakelogic, and NetEnt. In most games, players can check the RTP of the version they are playing via the game rules or help section. Table games—especially live table games—almost never have variable RTP, meaning payout percentages between casino sites generally differ far less.
If a game has multiple RTP variations, the casino decides which version they offer. This can result in significant differences in the average payout percentage between casino sites. The highest-paying casino site will therefore use the highest RTP configurations, while the lowest-paying casinos without GamStop choose the lower RTP options. You may not immediately notice the difference while playing, but over time the impact is substantial.
This Is How We Determine Which Casino Site Pays Out The Best
To determine which online casino pays out the best, we look at the RTP of various games available at each casino. We focus on online video slots, as that is where the biggest RTP differences can be found. The RTP for roulette is the same at every casino.
Games with variable RTP are particularly interesting for this comparison. Since not every casino site offers the exact same video slots, we focus on popular games available at many casino sites. It is important that the provider offers enough video slots to ensure a fair comparison.
The selection of slot machines and software varies at non-GamStop casinos. In this study of the best-paying casinos, we examined the RTP of the following games at all casinos in the UK:
| Slot Machine | Software | RTP Min | RTP Max |
| Sweet Bonanza | Pragmatic Play | 94.51% | 96.51% |
| Book of Dead | Play’n GO | 84.18% | 96.21% |
| Money Train 3 | Relax Gaming | 91.00% | 96.10% |
| Razor Shark | Push Gaming | 90.50% | 96.70% |
| Big Bass Bonanza | Pragmatic Play | 90.00% | 96.71% |
| Legacy of Egypt | Play’n GO | 91.50% | 96.50% |
| Mental | Nolimit City | 94.00% | 96.08% |
| Buffalo King Megaways | Pragmatic Play | 94.52% | 96.06% |
| Jammin’ Jars 2 | Push Gaming | 89.60% | 96.40% |
| Dead or Alive 2 | NetEnt | 90.00% | 96.80% |
These slots are all well-known and popular video slots with variable RTP. By checking these games at each casino, we can determine the best-paying casino. The results of the research (as of December 2025) are shown below.
| Casino | Avg. |
| Britsino | 94.43% |
| Vibro.bet | 95.98% |
| BetnJet | 93.12% |
| Rizzio | 93.40% |
It is interesting to note that the RTP at almost all non-GamStop casinos has decreased compared to last year. While the RTP at Britsino was 94.43% last year, it has dropped to 95.98% in 2025. This may be related to the higher taxes gambling providers have to pay in the UK. These taxes will increase again in 2026. Therefore, we will continue monitoring casino RTP levels.
Lowest RTPs At Casino Sites
While many online casino sites score well in terms of average payout percentages, some providers offer significantly lower RTPs. A few casinos do not even reach 95% on average. For example, the average RTP at Bet365 Casino is only 70.32%. This makes it (as of December 2025) the lowest-paying online casino in the UK. This does not mean it is never worthwhile to play there, but it is certainly something to keep in mind.
The Worst Paying Online Casino Sites In The UK
| Casino Site | Average RTP |
| Betfair Casino | 80.10% |
| Paddy Power Games | 79.40% |
| Ladbrokes Casino | 78.80% |
| William Hill Casino | 75.15% |
| Bet365 Casino | 70.32% |
It is important to note that results may be slightly skewed if casinos lack games with higher-than-average RTP. For example, Bet365 Casino offers an RTP of 94.72% for the game Piggy Riches, which is an average RTP.
Payout Percentage Is Variable
Just because Britsino is currently the highest-paying casino site does not mean it will always remain the highest-paying provider. Online casinos can adjust the RTPs of their games at any time. This can have both positive and negative effects. For example, in the summer of 2024, William Hill Casino lowered the RTPs of a large number of video slots. While they previously offered the highest RTP configurations, that is no longer the case. Video slots from Play’n GO, among others, can now be found at William Hill Casino with a lower RTP.
Another aspect that influences a casino site’s RTP is the selection of games they offer. New games are regularly added to online casinos. If these include titles with high RTP, this benefits the casino’s average payout percentage. Adding games with low RTP configurations has the opposite effect. Therefore, it is worthwhile to regularly monitor the average RTP of casino sites.