House edge explained

The house edge is the casino’s built-in mathematical advantage on a bet, shown as the average percentage of each stake it expects to keep over time. On single-zero roulette it is about 2.70%, so £10 on red costs around 27p on average, and the same principle applies to every game in a casino app.

By the Best Casino Apps UK team. Last checked 20 October 2026.

Key takeaways

House edge is the average share of each stake the casino keeps; RTP is the share it pays back.
It varies hugely by bet: banker in baccarat is near 1%, the tie bet is above 14%.
Expected cost = total amount staked × house edge, so playing longer costs more.
No betting system removes it; only the rules and the bets you pick change it.

Definition: Casino’s average advantage per bet
Formula: 100% − RTP
Single-zero roulette: About 2.70%
Double-zero roulette: About 5.26%
Can a system beat it?: No

What house edge means

Every casino game pays winning bets at slightly less than their true odds. That gap is the house edge. It doesn’t mean the casino wins every bet, or even most bets; it means that across a very large number of bets, the payouts fall short of the stakes by a predictable percentage.

House edge and RTP describe the same thing from opposite sides. A game with a 4% house edge has a 96% RTP. Table games tend to be quoted by house edge, slots by RTP, but you can convert either way by subtracting from 100%.

How house edge works: the roulette example

Roulette makes the maths easy to see. A single-zero wheel has 37 pockets. A straight-up bet on one number pays 35 to 1, but the true odds are 36 to 1. Bet £1 on every number across 37 spins on average and you win once (collecting £36 including your stake) while staking £37. The missing £1 out of £37 is 2.70%.

Add a second zero, as American roulette does, and the same bet loses £2 in every £38 on average: 5.26%. That one extra pocket nearly doubles the cost of playing, which is why our guides favour single-zero roulette. French tables with la partage halve the edge on even-money bets to about 1.35%, because you get half your stake back when zero lands.

House edge by game in a UK casino app

Game and bet	House edge (approx.)	Expected cost per £10 staked
French roulette, even-money bet with la partage	1.35%	About 14p
Baccarat, banker bet (5% commission)	1.06%	About 11p
Baccarat, player bet	1.24%	About 12p
European roulette, any standard bet	2.70%	About 27p
Typical 96% RTP slot	4%	About 40p
American roulette, most bets	5.26%	About 53p
Baccarat, tie bet paying 8 to 1	About 14.4%	About £1.44

Blackjack is the odd one out: its edge depends on the table rules and on your decisions. With basic strategy on favourable rules it can be well under 1%, but poor decisions raise it sharply, and side bets usually carry much higher edges than the main hand. Each game’s help screen in the app lists the return for every bet type, so check there rather than relying on general figures.

Why the house edge matters more the longer you play

The edge applies to every stake, including winnings you bet again. A player who deposits £50 and plays European roulette at £5 a spin for an hour could easily stake £1,000 in total. At 2.70%, the expected cost of that hour is about £27, even though they only deposited £50. Speed matters too, which is one reason UK rules now require at least 5 seconds per round on non-slot casino games and 2.5 seconds per slot spin.

This is also why bonus wagering has a cost. Wagering a £100 bonus 10x means £1,000 of stakes; on a 4% edge slot, that is about £40 of expected cost before you can withdraw. Our guide to wagering requirements in casino apps works through more examples, and game weighting explains why table games often count less.

Can any strategy beat the house edge?

No. Staking systems such as doubling after a loss change the size and pattern of your bets, but each bet still carries the same edge, so the total expected cost stays the same or rises because you stake more. Systems that chase losses can also hit the table maximum or empty a balance very quickly. Choosing lower-edge bets and setting a budget are the only levers that genuinely change what play costs you; bankroll management on mobile covers the budgeting side.

Finding the house edge inside a casino app

Open the game from the lobby, for example a roulette or baccarat table.
Tap the menu or ‘i’ icon and choose Help, Rules or Game Info.
Scroll to the payout or return section, which lists the RTP for each bet type.
Subtract that RTP from 100% to get the house edge for the bet you plan to make.

For game-by-game detail, see European roulette apps, baccarat apps and blackjack apps. Related terms: banker bet, volatility and RNG.

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Frequently asked questions

What is the house edge in simple terms?

It is the average percentage of every bet that the casino expects to keep over the long run. If a game has a 3% house edge, then across a huge number of bets the casino keeps about £3 of every £100 staked and pays the rest back as winnings. In the short term you can win or lose far more, but the edge works steadily on the total you stake. It is the opposite of RTP, so a 97% RTP game has a 3% edge.

Which casino game has the lowest house edge?

Among games common in UK casino apps, blackjack played with basic strategy on favourable rules usually has the lowest edge, often below 1%. Baccarat’s banker bet is close behind at about 1.06%, and French roulette with la partage drops even-money bets to about 1.35%. Exact figures depend on each table’s rules, so check the help screen in the game. A lower edge reduces the expected cost per pound but doesn’t make winning likely. See blackjack apps for how rules differ between tables.

Is the house edge different on a casino app?

No, the house edge belongs to the game and its rules, not to the device. A European roulette table has the same 2.70% edge whether you open it in an iPhone app, on the mobile website or on a desktop computer, because results come from the same server or live studio. What can differ is which game versions a particular casino offers, especially for slots with several RTP settings. The app vs mobile site guide covers the genuine differences, such as login and notifications.

How do I calculate how much the house edge will cost me?

Multiply the total amount you expect to stake by the house edge. Total stake is your bet size times the number of bets, including winnings you bet again. For example, 200 spins at 50p on a slot with a 96% RTP is £100 staked, and 4% of £100 is an expected cost of £4. One hour of £2 roulette bets at a spin a minute is £120 staked; at 2.70% that is about £3.24. Actual results vary widely; see volatility for why.

Why is American roulette worse than European roulette?

American roulette adds a double-zero pocket, giving 38 pockets instead of 37, while paying the same odds on winning bets. That extra pocket raises the house edge from about 2.70% to about 5.26%, nearly doubling the expected cost of every pound you stake. One bet on the American wheel, the five-number bet covering 0, 00, 1, 2 and 3, is higher still at about 7.89%. Our American roulette apps page explains the layout, and single-zero roulette covers the alternative.

Does the house edge mean the casino always wins?

No, it means the casino wins on average over a very large number of bets. Individual players win individual sessions all the time, and some leave ahead. But because the edge applies to every stake, the more you play, the more likely your results drift towards the expected loss. That is why it helps to treat gambling as paid entertainment with a set budget, and to use deposit limits and reality checks. Our guide to casino app limits shows how to set them on your phone.

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