How We Test Slot RTP - 5-Step Honest Method

Most review sites copy RTP numbers from provider PDFs. We do not. Every figure here comes from the in-game paytable at a real, live casino - then measured against the provider maximum. The gap between those two numbers is what we track.

Marcus Reid Updated May 2026 4 min read
33 Slots
tracked
2 Casinos
tested
0 Paid
rankings

Why Slot RTP Numbers Are Often Wrong

A slot does not have one fixed RTP. Most providers publish a range - say 94% to 96.5%. The casino picks which variant to run. They are not required to tell you which one they chose.

When a review site says "Book of Dead pays 96.21%", they are quoting the provider maximum set in lab conditions. What a specific casino runs could be lower. Here is what that difference looks like.

What most sites show 96.21%

Provider maximum RTP - copied from the provider PDF. Best-case figure. Rarely what you actually get at a specific casino.

Source: provider marketing PDF
What we show 95.00%

In-game RTP from the paytable at a real live casino. The version you are actually playing. That 1.21pp gap adds up.

Source: live in-game paytable

How We Test Slot RTP - 5 Steps

  1. Open a Real Account

    We register with the casino using a real account. No demo modes, no press access. The same experience any player gets when they sign up today.

  2. Find the In-Game RTP

    We open each slot and navigate to the paytable or game rules screen. The RTP shown there is what the casino is actually running. If no figure is shown, we record it as Hidden. That is a flag, not a pass.

  3. Record the Provider Maximum

    We check official provider documentation for the same title to find the highest available RTP variant. This is the benchmark every casino's figure gets measured against.

  4. Calculate the Gap

    We subtract the in-game RTP from the provider max. The result in percentage points is the RTP gap. A gap of 0.00pp means the casino is running the best version of that game.

  5. Publish the Raw Numbers

    Every reading is published openly: casino, slot, recorded RTP, provider max, and gap. Nothing is rounded. You can check our figures against the provider yourself.

How We Score Casino RTP Performance

Each casino gets an overall score out of 10. Lower average gaps score higher. A casino that hides figures gets penalised - if the number is not shown, you cannot make an informed choice.

RTP gap 50%
Transparency 30%
Sample size 20%
Average RTP gap vs provider max 50%
RTP transparency - games showing figures 30%
Sample size - slots checked vs total 20%

What the RTP Status Labels Mean

Every slot reading gets one of 3 status labels. Here is what each one means - and why Hidden matters as much as the numbers.

Match

Running at provider max

The gap is 0.00pp. Best version of this game. Best result for the player.

Below Max

Lower variant running

The casino chose a lower-paying variant. The gap in pp is shown. Across millions of spins, it is not nothing.

Hidden

RTP not shown in-game

No RTP found in paytable or rules screen. Either not displayed or buried. Hidden is a flag, not a pass.

How Slot RTP Data Looks in Practice

Here is a sample of real readings from our current dataset - so you can see exactly what we record and how the gap column works.

Sample RTP readings Real data - Wild Tokyo & Pistolo
Slot Casino RTP Provider max Gap
Book of Dead 96.21% 96.21% 0.00pp
Gates of Olympus 96.50% 96.50% 0.00pp
Big Bass Bonanza 96.71% 96.71% 0.00pp
The Dog House 95.00% 96.51% -1.51pp
Supreme Hot - 95.10% Hidden

The Honest Limits of Our Testing

We test real accounts, but we are not a regulator. We cannot access server-side configuration. What we check is what the casino shows a player inside the game - compared to what the provider publishes.

In practice, that in-game figure is what matters most to you. It is what the casino is telling you the game pays. If it is lower than the provider max, you now know by how much.

We update readings when we find a change. The "Last Checked" date on each slot page tells you when we last verified that figure.

Independence and Affiliate Disclosure

Some links on this site are affiliate links. If you visit a casino through our links and sign up, we may earn a commission. This does not change our scores. A casino with a poor RTP gap gets a poor score - full stop. No casino has paid to influence a reading or a ranking on this site.

Responsible Gambling

18+ only - gambling involves financial risk

RTP is a long-run theoretical average. In any single session, your results can differ a lot. If gambling stops being fun - or you are spending money you cannot afford - free help is at BeGambleAware.org and GamCare.org.uk.

Written by Marcus Reid

Marcus Reid, iGaming Data Analyst at CasinoWinRate

Marcus Reid

iGaming Data Analyst

I built this methodology after 4 years of watching review sites copy RTP figures straight from provider PDFs. The in-game figure is what players actually see. That is what we check. Every reading comes from a live, real-money account - no estimates, no recycled marketing numbers.

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