Choosing a game at an online casino is not only about what looks appealing. Over time, the casino tends to come out ahead, and that is built into every game through something called the house edge.
Understanding the house edge makes it easier to see how games are designed and what a casino may keep from total wagers across many plays. Terms like house edge and RTP sound technical at first, but once clear, they give useful context to players’ results.
This guide explains what the house edge means, how it is calculated, how it relates to RTP, and how it differs across popular games such as slots, roulette, blackjack, baccarat, and video poker.
What Does House Edge Mean For Players?
The house edge is a percentage that shows how much a casino may keep from each wager over time. It is built into the rules and payouts of every game and explains why the casino usually takes in more than it pays out.
For players, this helps explain why balances can swing in the short term yet tend to decrease with extended play. If a game has a house edge of 3%, for example, the casino may keep £3 from every £100 wagered in the long run. This average does not describe any single session, but the outcome across many bets.
Knowing the house edge helps with game choice. Some games tend to return more to players than others, but no strategy removes the house edge entirely. Playing should not be treated as a way to make money.
How Is House Edge Calculated?
House edge is calculated from the average amount a casino may keep from total wagers. It is shown as a percentage.
To work it out for a game, the probabilities of all possible outcomes are compared with the payouts for each one. The difference between what is staked and what is paid back, over many plays, produces the house edge.
For example, if a game takes £100 in bets and pays back £96 on average, the house edge would be 4%. The calculation is:
House Edge = (Total Amount Wagered – Total Amount Paid Out) ÷ Total Amount Wagered × 100%
Casinos use mathematical analysis and large-scale simulations to ensure these figures reflect the design of each game.
RTP And How It Relates To House Edge
RTP stands for Return to Player. It is a theoretical percentage showing how much of the total money wagered on a game might be paid back to players, on average, over time.
For example, a slot with an RTP of 96% means that, on average, £96 may be paid back from every £100 wagered, with £4 going to the casino.
House edge and RTP are closely linked and, together, total 100%. So, if a game has an RTP of 97%, the house edge would be 3%.
RTP is calculated over a large number of spins or bets, not individual sessions. Outcomes in a single sitting can differ from the theoretical figure.
With that link in mind, it helps to look at the typical ranges found in popular games.
House Edge In Popular Online Casino Games
Different online casino games come with their own house edge percentages. The figure can change with the game type, rule variations, and sometimes the way a player chooses to play.
Slots: Typical House Edge And RTP Ranges
Online slots often show RTP figures between about 92% and 97%, which means house edges usually range from roughly 3% to 8%. Each title is set up differently, so two slots from the same provider can still have noticeably different RTPs.
Roulette: European Vs American House Edge
In roulette, the house edge depends largely on the version. European roulette, with a single zero, has a house edge of about 2.7%. American roulette, which adds a double zero, increases it to around 5.26% because of the extra green pocket.
Blackjack: How Rules Affect The House Edge
Blackjack varies more than most games. Versions played with basic strategy usually sit around a 0.5% to 1% house edge. Rule changes, such as the number of decks, whether the dealer hits or stands on a soft 17, or the payout for a natural blackjack, can shift the edge up or down. Using basic strategy keeps the edge close to the published figure.
Baccarat: Standard House Edge By Bet Type
In baccarat, the house edge depends on the bet. The banker bet is usually about 1.06%. The player bet sits around 1.24%. The tie bet is much higher, often over 14%, which makes it costly over repeated play.
Video Poker: Pay Tables And House Edge
The pay table defines the edge in video poker. Full-pay versions of games like Jacks or Better can come in below 1% for those who use optimal strategy. Variants with reduced payouts for certain hands carry higher edges, so the specific pay table matters a great deal.
If you want to check a particular title rather than rely on averages, it is worth knowing where that information is published.
How Can I Find The House Edge For A Specific Game?
The game’s information or help menu is often the best place to start. Many online slots display RTP there. If it is not shown in the game, provider websites and independent review pages commonly list theoretical payout percentages.
Table games may not always display house edge in-game, but accepted figures for each rule set are widely documented. Remember that for games like blackjack or video poker, the edge depends on the rules and how closely a player follows the relevant strategy.
Knowing the numbers is only half the picture. It also helps to understand how results can move around those averages.
How Does House Edge Affect Short-Term Sessions And Variance?
House edge describes an average across many wagers. In short sessions, actual results can sit well above or below that average.
Variance is the term for these swings. Many slots are high variance, so balances can rise and fall sharply in the short term. Table games like blackjack or baccarat usually show smaller swings, although short-term outcomes can still differ a lot from the average.
As more bets are placed over time, results tend to move closer to the expected figures. In brief sessions, randomness has a larger effect.
This leads to a practical question many players ask: how can the house edge be used to estimate potential cost?
Estimating Expected Loss From House Edge
Estimating what might be lost in a session involves using the house edge and the total amount wagered, not just the starting balance.
Multiply the house edge, in decimal form, by the total staked. For example, staking £200 on a game with a 4% house edge gives an expected cost of £200 × 0.04 = £8. This is a long-term average. A single session can end higher or lower because results vary from bet to bet.
Common Misconceptions About House Edge
House edge does not predict what will happen in any individual session. It describes the long-run average only.
Playing longer or changing stake size does not reduce the house edge. It is built into the game’s rules and payouts.
Not all games share the same edge. Different rules and formats produce a wide range of figures, so it is worth checking the details for each game.
A game is not due to pay because it has not paid for a while. Each spin or hand is independent, and previous results do not affect future outcomes.
If you choose to play, set personal limits that suit your circumstances and take regular breaks. If gambling starts to affect your well-being or your finances, seek support early. Organisations such as GamCare and GambleAware offer free, confidential help.
**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.