One Game, Multiple Maths Models
When a slot provider launches a new game, it does not certify a single RTP. It certifies multiple versions — identical in appearance, different in mathematics. Your casino chooses which version to deploy. You are not told which one you are playing unless you check the game rules. This guide explains how the multi-tier system works, which providers offer how many tiers, and what the April 2026 release calendar reveals about where the floor is heading.
How the Certification Process Works
The concept is straightforward. A provider like <a href="/providers/pragmatic-play">Pragmatic Play</a> builds <a href="/slots/gates-of-olympus">Gates of Olympus</a>. It submits three mathematical configurations to a testing house for certification: 96.50%, 95.50%, and 94.50%. All three pass. All three are legitimate, tested, certified versions of the same game. The game's graphics, sound, bonus features, and volatility profile are identical across all three. The only difference is the long-term expected return to the player.
How Casinos Choose a Tier
The casino operator then selects which configuration to deploy. <a href="/casinos/bet365">Bet365</a> might choose 96.50%. Sky Vegas might choose 94.50%. Both are running Gates of Olympus. Both are running a certified, legal version. The player at Sky Vegas sees the same game, hears the same sounds, triggers the same bonus — and loses money approximately 2 percentage points faster.
How Many Tiers Each Provider Offers
Different providers offer different numbers of tiers. Pragmatic Play typically certifies three. <a href="/providers/play-n-go">Play'n GO</a> certifies five, ranging from approximately 96% down to approximately 84%. <a href="/providers/netent">NetEnt</a> certifies six to eight tiers for some titles, with <a href="/slots/starburst">Starburst</a> ranging from 96.09% down to 90.05%. <a href="/providers/hacksaw-gaming">Hacksaw Gaming</a> certifies four tiers — and in April 2026, Power of Ten shipped with a lowest tier of 86.20%. <a href="/providers/push-gaming">Push Gaming</a>'s Big Bamboo 2 launched with a lowest tier of 85.68%.
The Sub-90% Floor Is New
The sub-90% configurations deserve attention. Two years ago, a lowest certified tier below 90% was unusual. In April 2026, multiple providers are shipping games where the floor configuration returns less than 86p for every pound wagered over the long run. Whether any UK operator has selected these configurations is unknown — no casino discloses which tier it deploys except in the in-game info panel, and no regulator tracks it.
Nolimit City: Where the Floor Keeps Dropping
Nolimit City's trajectory illustrates the trend. Older Nolimit titles like Fire in the Hole were certified at 96.06% and 94.11% — a modest two-tier spread. More recent titles have seen expanded ranges, with Mental 2 reportedly certified down to 84.01%. The floor drops with each generation.
Red Tiger: Six Tiers, Six Points Apart
Red Tiger Gaming typically offers four to six tiers. Mystery Reels Megaways spans from 98.06% at its highest to 92.12% at its lowest — a 5.94 percentage point range on a single game. The highest tier is among the best RTPs available in the UK market. The lowest is among the most aggressive reductions. Same title, same reels, same bonus — nearly six points apart.
Big Time Gaming: A Legacy Catalogue Under Pressure
Big Time Gaming presents a special case. Legacy titles like Bonanza (96%) and White Rabbit (97.72%) were built as single-tier, fixed-RTP games. But after Evolution's acquisition, new BTG releases ship with variable tiers. TapCards launched in February 2024 with a range from 86.46% to 96.45%. The legacy catalogue is safe. New releases are not guaranteed to be.
The Practical Framework for Players
For players, the practical framework is simple. Always check the in-game info panel before committing to a session. The RTP shown there is the deployed figure at your casino. Compare it to the provider's published maximum — available on the provider's website, SlotCatalog, or BigWinBoard. If your casino is running a tier below the maximum, you are paying a hidden premium for the same game experience.
Gambling can be addictive. Please play responsibly. UK players experiencing problems can self-exclude via GAMSTOP or contact GamCare.
Compare verified RTP tiers across UK casinos
Stay informed on UK slot RTP:
Deployed RTP changes, new slot launches, and the data UK casinos don't advertise. One email per week. Unsubscribe anytime.