RTP and house edge explained
Every casino game keeps a share of what is staked. RTP and house edge are two ways of stating it.
By Ryan Jessop. Last checked .
Key takeaways
- House edge = 100% − RTP.
- Blackjack: about 0.5%. Slots: often about 4%.
- Averages over the very long run.
- Volatility is separate.
What they mean
RTP is the share of stakes a game returns over time; house edge is the share it keeps. A 96% RTP is a 4% edge.
By game
| Game | House edge | RTP | Average cost of £100 staked |
|---|---|---|---|
| Blackjack, good rules | Around 0.5% | 99.5% | £0.50 |
| Baccarat, banker | About 1.06% | 98.94% | £1.06 |
| European roulette | 2.70% | 97.30% | £2.70 |
| Slots | Often around 4% | 96% | £4 |
| American roulette | 5.26% | 94.74% | £5.26 |
Slots vary
| Slot | Developer | Default RTP | Volatility | Max win |
|---|---|---|---|---|
| Big Bass Bonanza | Pragmatic Play | 96.71% | High | 2,100x |
| Starburst | NetEnt | 96.09% | Low | 500x |
| Sweet Bonanza | Pragmatic Play | Varies by version (96.48% to 96.51% quoted) | High | 21,100x |
| Gates of Olympus | Pragmatic Play | 96.50% | High | 5,000x |
| Book of Dead | Play'n GO | 96.21% | High | 5,000x |
| Fishin' Frenzy | Blueprint Gaming (Reel Time Gaming) | 96.12% | Medium to high | 5,000x |
| Fluffy Favourites | Eyecon | 95.39% | High | 5,000x |
Developers' defaults; casinos may run lower versions.
One session
The figures are long-run averages. In a single session almost anything can happen, especially on volatile games.
Price a session: house edge calculator.
More guides: Casino verification explained, UK online casino rules and Casino budget guide.
Volatility
Two games with the same edge can feel completely different. Volatility describes how the return arrives: steadily, as in baccarat or a low volatility slot, or in rare large wins, as in a high volatility slot. It does not change the long-run cost.
Edge and speed
What you pay per hour is the edge times the amount staked per hour. A slot at 4% and 600 spins an hour of 20p costs about £4.80 an hour on average; blackjack at 0.5% and 60 hands of £2 costs about 60p.
For bonuses, the same arithmetic applies to wagering: stakes times edge is the average cost of clearing it.
Elsewhere in guides: UK online casino rules, Casino myths debunked, How to complain about a casino and How to choose an online casino.
Wider reading: Online gambling in the UK, Non-UK casinos: the risks, Top rated online casinos UK and Best payout casinos UK.
Offer terms dated 5 October 2026, from each casino's published conditions. Other casino details are reported by independent reviews. How we check. 18+. Free help: 0808 8020 133 or safer gambling.
Frequently asked questions
What is RTP?
Return to player.
What is house edge?
The casino's long-run share.
Which game has the lowest edge?
Blackjack.
Does RTP predict my session?
No.