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The online slots worth your evening, and what each one costs
"Best" depends on whether you like a steady ride or a big swing. These are the slots we rate, with the numbers that decide it.
Lists of "best slots" usually rank by how loud the marketing is. We rank by three numbers that are printed in every game's information screen: the return to player, the volatility and the top prize. Together they tell you what an evening on a game is likely to feel like and what it costs on average. Everything below was checked against the studios' published figures.
Which online slots pay back the most?
Return to player (RTP) is the share of all stakes a game pays back over a very long run. It is not a forecast for your session, but it is the fairest price tag a slot carries. The gap between 95% and 96.7% sounds small; across €100 staked it is the difference between the game keeping about €5 and about €3.29.
| Slot | Studio | Published RTP | Volatility | Top win |
|---|---|---|---|---|
| Big Bass Bonanza | Pragmatic Play | 96.71% | High | 2,100× stake |
| Gates of Olympus | Pragmatic Play | 96.50% | High | 5,000× stake |
| Sweet Bonanza | Pragmatic Play | about 96.5% | High | 21,100× stake |
| Book of Dead | Play'n GO | 96.21% (top setting) | High | see game rules |
One warning applies to all four: studios publish several RTP settings and casinos choose which to run. Book of Dead is the clearest case, with versions well below its 96.21% top figure. Open the information screen before staking real money; if the number is lower than the table above, you are on a reduced setting.
Which slot should a beginner start with?
Big Bass Bonanza. Ten fixed lines on a five-by-three grid, a dull base game and a free-spins round where a fisherman collects cash fish. Each retrigger lifts the multiplier from 2× to 3× to 10×, which is where the stories come from. The 2,100× ceiling is modest by modern standards, and that is part of the appeal: it behaves predictably enough to learn on.
Which slots suit players who want big swings?
Gates of Olympus
A tumbling grid where multiplier orbs drop during the free spins and add together at the end of a chain. The ante bet costs 25% more per spin and roughly doubles the chance of triggering free spins, without improving the return. At €0.50 a spin and around 450 spins an hour, you stake about €225 and the average cost at 96.5% is about €8. A dry hour can cost far more than that.
Sweet Bonanza
The same engine dressed as a sweet shop, with candy bombs from 2× to 100× in the bonus round and a 21,100× ceiling. Studio-rated high volatility, and two-hundred-spin droughts are part of the experience. A sensible rule is to hold at least 200 stakes: on €50 that means 25p-sized spins, or €0.25 in a euro cashier, not €1.
What about the classic book slot?
Book of Dead is the one-feature slot everyone knows: land three books, get ten free spins with one symbol that expands across the reels. Long runs with a premium symbol are rare by design. It is a cleaner, simpler game than the tumbling grids, and a good test of patience.
Where do the UK pub favourites fit in?
Many British players first met slots on high-street machines, and titles like Rainbow Riches and Fishin' Frenzy carry that familiarity. Worth knowing: the classic Rainbow Riches publishes around 95%, lower than the four picks above, so it is a game to enjoy rather than to grind a bonus on. If you like the fishing theme, Big Bass Bonanza is the modern cousin with a higher published return.
Can I try these slots for free first?
Not the four above at Casino Purple: Pragmatic Play titles do not run in demo there. Around 590 other games do, mostly classic reels from Novomatic, Greentube, Amatic and Wazdan. Our Casino Purple games guide lists the demo shelves. If you want to see how the welcome match interacts with slot play, the payments page shows how the code is applied at the first deposit.
Is a jackpot slot ever the "best" slot?
Only if you know what you are buying. A progressive jackpot is funded by a slice of every stake, which comes out of the running return. For long sessions, a game without a jackpot usually pays back more in ordinary play.
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18+. A slot's RTP is an average over millions of spins; budget for the bad hour, not the average one.
Online slots FAQ
What is the highest RTP slot on this list?
Big Bass Bonanza, at 96.71% on its published version.
Do online slots have hot and cold streaks?
No. Every spin is independent and the game has no memory. A long losing run does not make the next spin more likely to pay.
Does the ante bet in Gates of Olympus improve my odds?
It roughly doubles the chance of free spins for 25% more per spin, but it does not change the return to player.
Where can I play these slots?
All four are in the Casino Purple lobby, where PURPLE100 adds a 100% match to the first deposit.
How do I check a slot's RTP?
Open the game's information or help screen. The figure there is the setting in force at that casino.