Slot basics

Why the same slot has different RTPs

The same slot, with the same graphics and features, can return 96% at one casino and 91% at another. Both are legal and certified. Here is how RTP versions work and how to check the one in front of you.

Updated 9 October 20264 min readFigures from the WildmarkSlots catalogue · How we work

A row of identical "On the Money" slot machines at the Tropicana, Las Vegas — Photo: Carol M. Highsmith, Public domain, via Wikimedia Commons

How RTP versions work

A studio builds one game and certifies several sets of maths for it, each with a different RTP. The paytable and features usually look identical; the difference is in how often symbols land or how bonus outcomes are weighted. The casino chooses which version to install, often for its whole market.

Rich Wilde and the Book of Dead by Play'n GO is recorded at 96.21%, 94.25%, 91.25%, 87.25%, 84.18%: a gap of 12.03 points between the highest and lowest version.

How big the gap is

WildmarkSlots records several versions for 737 slots. On those, the lowest version is on average 8.4 points below the headline RTP, and the widest gap is 13.0 points.

Session: 1 per spin, 600 spins (about an hour)
96% version → average cost 24
88% version → average cost 72  (three times as much)

Same game, same bet, same time, and an average cost three times higher. That is why WildmarkSlots shows every recorded version, not only the best one. See them all in slots with several RTP versions.

Why studios offer several versions

The arrangement is simple. The studio licenses a game to many operators, each with its own market and business model. Offering a few certified settings lets an operator pick the one that fits its business. For a player the consequence is just as simple: a lower RTP means the operator keeps more of every amount wagered, and the player pays the difference.

Nothing about this is hidden in the maths: every version is tested and certified for the markets it is sold in. What is easy to miss is that there is a choice at all, because the game looks identical. A fair comparison between two games is only possible when you compare the version you will actually play.

What it costs over a month

A small gap per spin becomes a clear difference over time. Suppose you wager 500 a week on one game:

96% version → 500 × 4% = 20 per week → about 80 in four weeks
92% version → 500 × 8% = 40 per week → about 160 in four weeks

You would not notice the difference in any single evening, because short sessions are dominated by chance. You would notice it, on average, over many sessions. This is the same long-run reasoning as in what is RTP, and you can run your own numbers in the RTP calculator.

How to check the version you are playing

Open the game and find the menu, info (i) or paytable button.
Look in the game rules or help pages for "RTP", "theoretical return" or "expected payback". It is often near the end.
Compare it with the versions listed on the game's WildmarkSlots page. If it matches a lower version, you know the price before you play.
If you cannot find it, ask the casino's support which RTP its version uses.

Which studios publish versions

Some studios publish every version on their game pages and the sources record them; for others, the open data lists a single RTP. A single listed RTP does not prove there are no other versions, so WildmarkSlots says "recorded" rather than "only". The methodology lists which studios' versions are tracked.

How WildmarkSlots shows versions

Of the 3,708 slots on WildmarkSlots, 737 (about 20%) have more than one recorded RTP version. On those pages we show the headline RTP, which is the highest version, and list the others next to it. The value score uses the headline figure, and the how we rate page explains why and what that means for comparing games.

Browse them in slots with several RTP versions, or start from the high RTP slots if you want the best published figures first. Remember that a high headline RTP is only the best case. The version at the site where you play is what decides your cost.

Comparing two games fairly

Suppose Game X is recorded at 96.5%, 94% and 92%, and Game Y has a single recorded RTP of 95.5%. Which is cheaper depends on the version you actually meet:

Game X at 96.5% → cost per 1,000 wagered: 35
Game X at 92%   → cost per 1,000 wagered: 80
Game Y at 95.5% → cost per 1,000 wagered: 45

If the site you use runs X at 96.5%, it beats Y. If it runs X at 92%, Y costs little more than half as much. A list that shows only the headline figure for X would rank it first without this context, which is why a single RTP number can mislead. Look for the range, then look for the figure inside the game.

The headline is also a best case, so it is the number to treat with the most caution. If you are choosing between games and cannot confirm the version, take the lowest recorded figure as the likely price and treat anything better as a bonus rather than a plan.

Versions can change over time

An operator can swap the installed version of a game, and studios add new versions as they release updates. The figure you saw last month may not be the one in the game today. This is one more reason to read the RTP in the rules each time you start a new session on a game you have not played recently, and to treat any list, including ours, as a record of what has been published and not as a statement about one particular site.

Habits that protect you

Read the RTP in the game rules before you play, every time you try a new site.
If the figure is low compared with the versions listed on WildmarkSlots, pick another game, or play less.
Do not rely on a demo to tell you the version: a demo may run a different setting from the one an operator uses.
Keep a session budget whatever the figure; see how to set a slot budget.

Frequently asked questions

Is a lower RTP version legal?

Yes. Every version is certified for the markets it is sold in. A lower version is simply a more expensive way to play the same game.

Do casinos have to tell me the RTP?

Many regulated markets require games to display their RTP in the help or paytable screens. Where it is shown, the game itself is the most reliable place to check.

Does WildmarkSlots know which version a casino uses?

No. Casinos do not publish this consistently, and it can change. We list every recorded version so you can compare it with the figure inside the game.

Can I choose which RTP version I play?

No. The operator installs the version, and the player has no setting for it. What you can do is read the figure in the game rules, compare it with the versions listed on WildmarkSlots, and decide whether the price suits you.

Do all slots have more than one RTP version?

No. WildmarkSlots records several versions for 737 of 3,708 slots, about 20%. Many games have one recorded RTP, though that does not prove no other version exists.

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