Return to Player (RTP) is the most useful single metric for comparing slot machines. This guide explains what RTP means in practice for Irish players, which well-known slots have published RTPs above 97%, and — critically — what RTP cannot tell you about your session.
What Is RTP and How Is It Calculated?
RTP is the theoretical percentage of all wagered money that a slot game pays back to players over an extremely large number of spins (typically 10 million or more in testing). It is set by the game developer and independently verified by testing laboratories such as eCOGRA, iTech Labs or GLI before the game is licensed.
Example: A game with 97% RTP theoretically returns €97 for every €100 wagered. The remaining 3% (the house edge) is the mathematical cost of playing that game over time. Compare this to a 94% RTP game with a 6% house edge — the same €100 of wagering costs €6 instead of €3 on average.
Well-Known Slots with Published RTPs Above 97%
The following are examples of games with developer-published RTPs at or above 97%. RTPs can be verified in each game's paytable or information section. Note that some casinos adjust RTP within the allowed range — the actual live RTP at a specific casino may differ.
| Game | Developer | Published RTP | Volatility |
|---|---|---|---|
| Mega Joker | NetEnt | 99.0% | High |
| Goblin's Cave | Playtech | 99.3% | Low |
| Blood Suckers | NetEnt | 98.0% | Low-Medium |
| 1429 Uncharted Seas | Thunderkick | 98.6% | Medium |
| Jackpot 6000 | NetEnt | 98.9% | High |
| Kings of Chicago | NetEnt | 97.8% | Medium |
RTPs as published by developers. Verify in-game before playing. Not an endorsement or guarantee of winnings. 18+ only.
What RTP Does Not Tell You
RTP is calculated over millions of spins — it has limited predictive value for a single session of 100 or 500 spins. High-RTP games can deliver losing sessions; low-RTP games can deliver winning sessions. The factor that matters more in short sessions is variance (volatility):
- Low variance, high RTP (e.g. Blood Suckers): frequent small wins, slow bankroll erosion, less exciting but more predictable.
- High variance, high RTP (e.g. Mega Joker): rare but potentially large wins; long losing runs are common despite the high RTP.
Bonus Wagering and Effective RTP
If you are playing with a bonus, the stated wagering requirement affects your expected value. A 40x wagering requirement on a €100 bonus means wagering €4,000 to convert the bonus to cash. If you play a 97% RTP slot, you are statistically expected to retain 97% of each spin's value — but €4,000 × 3% house edge = €120 expected cost of wagering. The effective return depends on both the bonus size and the RTP of the game you choose. Games with low RTP are slower to wager through, costing more statistically.
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Frequently Asked Questions
RTP stands for Return to Player — the theoretical percentage of wagered money a slot pays back over millions of spins. A 97% RTP slot theoretically returns €97 for every €100 wagered long-term. It is a mathematical average, not a guarantee for any single session.
A higher RTP means a lower house edge, which statistically reduces the cost of play over many sessions. In a short session, any outcome is possible regardless of RTP.
RTPs are set by game developers and verified by independent testing labs. Licensed casinos must offer games with the declared RTPs. Some casinos adjust RTP within the allowed range — verify the actual RTP in the game's information panel.
Yes. The stated RTP includes all game features. However, variance means bonus features can produce very high or very low returns in a single session — RTP averages out over large sample sizes.