Understanding the house edge is an important part of online casino play, yet many players may not know exactly how it works or why it matters. With so many games available online, knowing about house edge helps highlight how each game is designed and what this could mean for someone’s experience.
This blog explores what house edge is, how it is calculated, and how it differs from Return to Player (RTP). You’ll also find clear examples using familiar games such as roulette, blackjack, and slots.
We then look at whether skill can influence the figures, whether online casinos can alter house edge or RTP, and how to use this knowledge when choosing games. There is also a simple guide to expected loss, plus practical pointers to help you stay in control if you choose to play.
Read on to learn more.
What Is House Edge?
House edge is a term used in gambling to describe the built-in advantage that a casino has over players for each game offered. It is shown as a percentage and indicates, on average, how much of each bet the casino may keep over many rounds of play.
For example, if a game has a house edge of 2%, the casino expects to keep £2 out of every £100 wagered over time. The rest is paid out as winnings.
Every casino game has its own house edge, set by the rules and design of the game. This is how casinos generate revenue and continue providing games. It does not predict what any individual player may win or lose in a single session, as short-term outcomes can vary.
How Is House Edge Calculated?
House edge is calculated by comparing the average amount a player might lose on a bet to the original amount wagered, then expressing that result as a percentage.
For example, if a game returns £97 to players out of every £100 bet over many rounds, the house edge is 3%. This means the casino keeps £3, on average, out of every £100 staked.
Different games use different formulas based on their rules and payouts. In roulette, for instance, the calculation considers all possible outcomes and the odds of each. These figures reflect long-term averages rather than what happens in any single playing session.
With that foundation in place, it helps to see how RTP relates to the same idea.
House Edge Versus Return To Player (RTP): What’s The Difference?
House edge and Return To Player (RTP) are two sides of the same coin but framed differently.
House edge shows the percentage of each bet the casino may keep over a large number of games. RTP is the theoretical average percentage of total stakes that may be paid back to players over time.
For example, if a slot has an RTP of 96%, it means that, on average, £96 is returned for every £100 wagered over the long run. The house edge here would be 4%. Neither number guarantees individual results, but together they explain how a game is expected to behave across many plays.
Knowing this, the next piece of the puzzle is how specific rules can shift those percentages.
How Do Game Rules Affect House Edge?
The rules of a casino game can make a noticeable difference to the house edge. Even small changes may affect the percentage that the casino keeps over time.
In blackjack, using more decks or changing how the dealer must play certain hands can increase the edge. In roulette, adding an extra zero nudges the odds further towards the house.
Some slots include bonus features or alternative paylines that can influence the long-term return depending on how often those features are triggered. In baccarat or craps, different bet types each carry their own edge.
Understanding the rules and features of a game gives a clearer picture of how its house edge works. So what do these differences look like in popular games?
Typical House Edge Examples For Common Casino Games
Different casino games have different house edges. The percentage varies based on rules, bet types, and features. Here are some examples from well-known online casino games.
Roulette (European and American)
European roulette usually has a house edge of 2.7%, as it features a single zero on the wheel. American roulette has both a single and double zero, which increases the house edge to around 5.26%.
These differences are due to the extra double zero in American roulette, which slightly lowers the odds for players. Anyone choosing to play may want to be aware of which version they are playing.
Blackjack (Rule Variations and Dealer Rules)
Blackjack house edge varies depending on rules and the number of decks. With player-friendly rules, the house edge might be around 0.5%. Less favourable rules, such as the dealer hitting on a soft 17 or a lower payout for blackjack, may push the house edge higher.
Checking the table rules before playing may help players understand the edge in that specific game.
Online Slots (RTP and Volatility)
Online slots usually display their RTP, often ranging from about 92% to 97%. This translates to a house edge of roughly 8% down to 3%. Volatility is a separate factor related to how often wins occur and how large payouts may be, and it does not change the house edge.
Each slot title sets its own house edge, which is usually listed in the game’s information.
Baccarat and Craps
Baccarat has a house edge of around 1.06% on the banker bet and about 1.24% on the player bet. Tie bets generally have a much higher house edge.
Craps presents several betting options. Some bets, such as the pass line, have a house edge close to 1.4%, while more complicated bets can have higher figures.
That raises a common question: can player decisions meaningfully shift these numbers?
Does Player Skill Change The House Edge?
For most online casino games, the house edge remains the same regardless of how a person plays. Games such as roulette, baccarat, and slots are not influenced by player decisions once a bet is placed, so everyone faces the same mathematical advantage held by the casino.
Some games, such as blackjack and certain forms of video poker, do involve strategy. Using optimal decisions in these games may reduce the edge when compared with random choices, although it does not remove it. Even where strategy helps, results vary from session to session.
Can Online Casinos Alter The House Edge Or RTP?
Online casinos do not generally set the house edge or RTP themselves. These figures are usually built into the game software by the provider that creates the game, so the same title will typically have the same underlying maths wherever it appears.
Some games offer multiple RTP or house edge settings that a casino can choose from before making the game available. When that is the case, the selected RTP should be shown in the game’s information.
In the UK, licensed online casinos must display accurate information about RTP where possible and follow rules set by the Gambling Commission. Randomness and fairness are tested by independent organisations. Knowing where these numbers come from can help when deciding what to play.
How To Use House Edge When Choosing Games?
Understanding house edge can help players compare games and decide what suits their preferences. In general, games with a lower house edge return a greater percentage of wagers to players over time.
Published house edge or RTP figures are usually shown in a game’s information section or on the casino site. Players who prefer longer sessions often look to lower-edge games such as blackjack or certain types of video poker. Higher-edge games, such as some slots, may include a wider mix of features, but a larger share of total stakes is kept by the casino in the long run.
Remember that house edge represents a long-term average, not a prediction for a single visit. A simple way to put numbers on this is to look at expected loss.
What Is Expected Loss And How Do I Calculate It?
Expected loss is a straightforward way to estimate how much money might be lost on average when playing a casino game with a given budget. It is a theoretical figure based on the game’s house edge and the total amount staked.
To calculate expected loss, the following formula may be used:
Expected Loss = Total Amount Wagered × House Edge
For example, if someone wagers £100 on a game with a house edge of 5%, the calculation would be £100 × 0.05, resulting in an expected loss of £5 over time.
This gives a clearer view of how the house edge could affect funds across many bets or spins, while acknowledging that actual results often differ over short sessions. If gambling starts to affect your well-being or finances, seek support early. Independent organisations such as GamCare and GambleAware offer free, confidential help.
Understanding house edge, RTP, and expected loss provides a realistic picture of how casino games work, so anyone who chooses to play can make informed, measured decisions.
**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.