Slot machine odds
What can and cannot be known about a slot machine's chances.
By Ryan Jessop. Last checked .
Key takeaways
- House edge: about 4% online.
- Hit rate is not win rate.
- Top prizes are very rare.
- Reel odds are hidden.
In shortAn online slot machine keeps about 4% of stakes over time. The chance of any particular prize is not published, because virtual reels hide the true odds.
House edge
| Slot | RTP | House edge | Cost of £100 staked |
|---|---|---|---|
| Big Bass Bonanza | 96.71% | 3.29% | £3.29 |
| Gates of Olympus | 96.50% | 3.50% | £3.5 |
| Book of Dead | 96.21% | 3.79% | £3.79 |
| Fishin' Frenzy | 96.12% | 3.88% | £3.88 |
| Starburst | 96.09% | 3.91% | £3.91 |
| Fluffy Favourites | 95.39% | 4.61% | £4.61 |
Hit frequency
How often any win lands. Many wins are smaller than the stake, so a high hit rate can sit beside a falling balance.
Why the old sums no longer work
On a mechanical machine with 20 symbols per reel, the top prize was a 1 in 8,000 chance. A virtual reel has hidden weights, so the only reliable figures are RTP and volatility.
Keep reading: Paylines and ways to win, Video slot machines, Big Bass Bonanza slot machine and Coral Casino slot machines.
Go further: The BAR symbol, Low stake slot machines and Pub slot machines.
Keep reading: Starburst vs Book of Dead, Fishing slot machines, Pays-anywhere slot machines and How to play a slot machine.
Slot figures are developers' published defaults, each confirmed against two sources; the version at your casino can differ. UK land-based stake and prize limits and online rule dates were checked against Gambling Commission and licensing authority sources on 6 October 2026. History follows commonly cited accounts. Offer terms dated 5 October 2026. How we check. 18+. Free help: 0808 8020 133 or safer gambling.
Frequently asked questions
What are the odds on a slot machine?
About a 4% house edge online.
What is hit frequency?
How often any win lands.
Can I work out the jackpot odds?
No.
Which slot has the best odds?
Of our seven, Big Bass Bonanza.