Many players notice that the casino tends to come out ahead, but the reason is not a secret. It comes down to the house edge, a built-in mathematical advantage that sits behind every game.
Understanding how the house edge works helps when comparing options like slots, blackjack, roulette, and baccarat. Rules and variants matter too, as do live dealer formats and side bets.
This guide explains what the house edge is, how it is calculated, how it differs from RTP and volatility, how common games compare, and how to use the information when choosing what to play.
Read on to learn more.
What Is The House Edge In Online Casinos?
The house edge describes the average share of each stake a casino keeps over time. It is shown as a percentage.
If a game has a 5% house edge, then across a very large number of bets, the casino expects to retain about £5 for every £100 wagered. The remaining £95 is returned to players as winnings overall, though individual sessions will vary.
Every casino game builds this edge into its rules. It does not predict what will happen in any one sitting; it simply reflects long-run outcomes across thousands of plays. With the basics in place, the natural next question is how those numbers are worked out for different games.
How Is House Edge Calculated For Different Games?
The calculation depends on each game’s structure and rules. In simple terms, it compares what the casino expects to win to the total amount wagered by players.
For slots, the house edge is the gap between total bets and total payouts over a vast sample of spins. This is set by the game’s programmed payout profile and paytable.
In blackjack and baccarat, the figures reflect both the rules and, for blackjack in particular, decisions that follow optimal strategy. Elements such as the number of decks, whether the dealer stands on soft 17, or the availability of doubling and splitting all shift the maths.
Roulette is driven by the layout of the wheel. The green zero creates outcomes that do not pay on most bets, and an additional double zero increases that effect.
To protect players, commercial games are tested by accredited laboratories to confirm that results align with the stated probabilities and that random number generators behave as advertised. Understanding the calculation is useful on its own, but it becomes clearer still when compared with RTP and volatility.
House Edge Versus RTP And Volatility: What's The Difference?
These terms describe different aspects of a game.
RTP, or Return to Player, is the theoretical proportion of total stakes that a game pays back to players, on average, over the long run. A slot with a 96% RTP is expected to return about £96 out of every £100 wagered across many sessions.
House edge is the complement to RTP. If a game has a 96% RTP, its house edge is roughly 4%. It represents the casino’s long-term share of wagering.
Volatility relates to the pattern of payouts. High-volatility games may produce fewer but larger prizes. Low-volatility games tend to deliver smaller returns more frequently. It does not change the underlying RTP, but it affects how results feel from session to session.
With the concepts separated, it helps to look at typical figures for popular games.
Typical House Edge For Slots, Blackjack, Roulette And Baccarat
Different games carry different long-term expectations because their rules and payout structures vary.
Online slots commonly range from about 2% to 10% or more, depending on the individual title’s RTP and features.
Blackjack often sits between roughly 0.5% and 2% when played with basic strategy, though unfavourable rules or side bets can push it higher.
Roulette depends on the wheel. European roulette, with a single zero, is typically 2.7%. American roulette, with both zero and double zero, rises to around 5.26%.
Baccarat’s main bets tend to be lower: the banker bet is about 1.06% and the player bet about 1.24% in the common format, while the tie bet is typically much higher, often above 14%.
Those headline numbers can and do shift with small rule changes, which is why variants matter.
How Game Rules And Variants Affect The House Edge
Small adjustments in rules can make a noticeable difference to the edge.
In blackjack, more decks generally help the house, while options such as surrender can reduce the edge for players. Whether the dealer hits or stands on soft 17, the way doubling after splits is handled, and restrictions on re-splitting also move the percentage.
Roulette’s clearest lever is the number of zeroes, but table rules like en prison and la partage on even-money bets can improve returns compared to wheels that do not offer them.
Slot games each have their own programmed RTP and feature set. Changes to paytables, bonus frequency, or the mix between small line pays and feature-driven prizes influence the long-term profile.
In baccarat, the standard banker and player bets are well known, but side bets often carry higher edges. Commission rules on banker wins also affect the exact percentage.
Understanding these levers makes it easier to read a game’s rules screen and spot what might nudge the maths. With that in mind, many players wonder whether live dealer versions change the picture.
Do Live Dealer Games Have The Same House Edge?
Generally, yes. Live dealer tables follow the same core rules as their digital counterparts, so the underlying house edge is usually similar. Where differences appear, they tend to come from optional side bets or small rule tweaks introduced for a specific table.
Live formats add social interaction and a real-time dealing environment, but those elements do not alter the probabilities. If a live game lists additional features, it is worth checking the details so you understand how they affect the numbers.
Even where the edge is the same, there is more to choosing a game than percentages alone.
Are Lower House Edge Games Always Better For Players?
A lower house edge means a game is expected to return a higher share of stakes over time, which can help a budget stretch further. That said, it does not automatically make a game the best fit.
Volatility affects how results unfold. Some players prefer the steadier rhythm of lower-volatility games, while others enjoy titles with larger but less frequent prizes. Presentation, pace, and features such as bonus rounds or side bets also shape the experience.
A game with a low edge can still lead to higher overall spend if played for long periods or at stakes that do not suit the player. Setting a budget before starting and keeping sessions in check remains sensible, whatever the edge. With preferences and priorities in mind, the final step is putting the information to work.
How To Use House Edge Info When Choosing Which Games To Play
House edge is a useful benchmark when comparing games. As a rule of thumb, a lower edge suggests more of your total wagering is returned over the long run, but it should sit alongside other factors when deciding what to play.
Look at the published figures and rules for the specific version you are considering. In blackjack, for example, small rule changes and basic strategy make a real difference. In roulette, the wheel type and any even-money rules matter. For slots, check the stated RTP for that exact title and be aware that feature-heavy games can feel very different even on similar percentages.
Above all, approach casino games as paid entertainment rather than a source of profit. Never stake more than you are prepared to lose, set personal limits that suit your circumstances, and take regular breaks.
**The information provided in this blog is intended for educational purposes and should not be construed as betting advice or a guarantee of success. Always gamble responsibly.