Payout percentage, or return to player (RTP), is the single most useful number on any casino page. It tells you how much of all staked money a game or site returns to players over time, expressed as a percentage. On a 96% RTP slot, roughly £96 of every £100 wagered comes back across millions of spins. The casino keeps the rest as its edge. Understanding how that figure is calculated, where it applies and how operators can present it differently is essential for anyone who wants to read an offer like a contract rather than a headline. Read more about this at check the list.
In the United Kingdom, RTP disclosure is taken seriously. Licensed operators generally publish per-game figures, and testing houses audit the random number generators behind them. That transparency matters because a few percentage points of house edge compound quickly across a long session. A game at 94% and one at 97% look similar on the surface, but the difference in expected loss over thousands of spins is substantial. Offshore sites not on Gamstop are not bound by the same disclosure rules, which is exactly why the clauses deserve close reading.
It is also worth separating the two numbers players often confuse: theoretical RTP and actual results. RTP is a long-run average, not a promise about your next hundred spins. Variance means short sessions can swing wildly in either direction regardless of the published figure.
How Payout Percentages Are Calculated and Where the Edge Lives
Every casino game carries a mathematical house edge built into its rules. European roulette, with a single zero, returns about 97.3% to players; the American double-zero layout drops that to roughly 94.7%. Blackjack played with basic strategy can reach 99.5% or higher depending on rule variations. Slots vary enormously, typically from around 92% to 98%, and progressive jackpot titles often run lower on the base game because a portion of each stake feeds the prize pool.
Skill also shifts the effective return. A blackjack table advertised at 99.5% assumes optimal play; a casual player making errors may see an effective RTP several points lower. The same principle applies to video poker, where the pay table and the player’s strategy decisions together determine the real figure.
Operators sometimes publish ranges rather than fixed numbers, or list a game’s RTP in a help screen rather than on the tile itself. When you review an offshore casino offer, check whether the stated percentage refers to a specific game, a game category or a site-wide average. A site-wide average tells you very little about the slot you actually want to play.
Reading RTP Claims on Offshore and Non Gamstop Sites
Offshore operators outside Gamstop self-exclusion arrangements often promote high RTP as a headline feature. Some genuinely deliver it. Others bury the detail in terms that allow the figure to be calculated differently, or apply the advertised percentage only to selected titles. A useful habit is to open the game’s information panel and confirm the RTP shown there matches the marketing claim.
Bonuses complicate the picture further. Wagering requirements mean your stake is recycled several times, and the house edge applies to every cycle. A 96% game with a 40x wagering requirement on a £100 bonus means £4,000 of turnover before withdrawal, with an expected cost of around £160 at that RTP. That arithmetic, not the bonus headline, determines whether the offer has value.
Licensing jurisdiction matters too. Curacao-licensed casinos operate under different audit and disclosure standards from UK-licensed ones, so published RTPs may be less rigorously verified. None of this makes offshore play automatically poor value , it simply means the player carries more of the verification burden.
Practical Checks Before You Stake a Penny
Treat RTP as one clause among many in the contract you are signing with your stake. The table below shows typical ranges to benchmark against.
| Game Type | Typical RTP Range | House Edge |
|---|---|---|
| Blackjack (basic strategy) | 99.0% – 99.6% | 0.4% – 1.0% |
| European roulette | 97.3% | 2.7% |
| Online slots | 92% – 98% | 2% – 8% |
| Progressive jackpot slots | 88% – 94% | 6% – 12% |
Before depositing, confirm three things: the RTP of the specific game you intend to play, whether bonuses carry game-weighting restrictions that exclude high-RTP titles, and whether the operator publishes independent testing certification. Games weighted at 50% or less toward wagering effectively double the cost of clearing a bonus.
Finally, remember that RTP describes the machine, not your session. Responsible play means setting deposit limits in GBP before you start and treating any return as part of a long-run average rather than a forecast. Players aged 18 and over should always prioritise control over chasing percentages.