Every casino game has a house edge: the share of each bet the casino expects to keep over thousands of rounds. It does not decide one session. A game with a 5% edge does not take exactly $5 from every $100 you stake tonight; it takes about 5% of everything staked on it over time. Odds describe the chance of one outcome, and the house edge describes the casino's built-in margin across all of them. This guide shows how to work out the edge, what it is in the games you play on a phone, and how to keep it low. More guides are in our mobile casino guides.
How to calculate the house edge
Two formulas give the same answer:
- House edge = (1 − expected payout) × 100%
- House edge = 100% − RTP
The second one is the one you will use on a phone, because most games publish their Return to Player (RTP). RTP and house edge always add up to 100%.
- Open the game's Help, Info or Rules screen.
- Find the stated RTP.
- Subtract it from 100%.
A slot at 96.5% RTP has a 3.5% edge: over time the casino keeps $3.50 of every $100 wagered. In blackjack the edge is about 0.5% with basic strategy. European roulette sits at 2.70% and American roulette at 5.26%.
You do not need a special app for this. A phone calculator and the game's help screen are enough, and review sites that list RTPs let you compare games before you open them.
The house edge is the casino's expected share of stakes over a long series of independent rounds. Each outcome has a probability and a payout. Multiply those two numbers for every outcome, then add the products. That sum is the expected payout of one stake. Subtract the expected payout from 1. The remainder is the house edge. RTP states the same remainder from the player's side of the ledger. A published RTP of 96% means the expected payout is 96 cents of each dollar staked. The house edge on that game is 4%. The arithmetic is identical for a slot, a roulette wheel and a crash round. Only the inputs change: the paytable, the number of pockets, or the distribution of crash multipliers. Check the figure in the game you opened. A studio's headline RTP can differ from the setting the casino actually runs.
Does the phone change the house edge?
No. A licensed casino runs the same random number generator and the same payout maths on mobile and desktop, and it cannot change the edge by device. What the phone changes is your exposure: how much you stake against that edge.
- Faster rounds. Tapping is quicker than clicking, so you play more rounds per hour.
- Short, frequent sessions. A few minutes on the bus hides the long-run pattern, but those minutes add up.
- Always within reach. Access around the clock raises the total you wager over a month.
- Fewer low-edge variants. Some mobile lobbies carry fewer of the low-edge table versions.
- Mis-taps. An accidental tap can place a bet you did not mean or a wrong move in blackjack.
A licensed mobile casino keeps one random number generator for a game title. The phone client sends the stake and the chosen bet. The server draws the outcome. The draw does not read the screen size, the operating system or the tap speed. The edge stays fixed because the probabilities stay fixed. What changes on a phone is the number of stakes you place in an hour. A faster round rate puts more money through the same percentage. The monthly cost is the edge times the total stake, so a higher round rate raises the cost even when the percentage is unchanged. Turn turbo and autoplay off when you want fewer rounds against that percentage.
House edge by mobile game type
Each game type has its own payout structure, so the edge ranges from under 1% to over 30%.
| Game | Typical house edge | Why |
|---|---|---|
| Blackjack | 0.5%–1% | With basic strategy and a 3:2 blackjack payout |
| Video poker (Jacks or Better) | 0.5%–2% | With optimal holds |
| Baccarat | 1.06%–1.24% | 1.06% on the banker bet |
| Craps (pass line) | 1.4% | The pass line is the lowest-edge craps bet |
| Crash games | 1%–3% | Most run at 97%–99% RTP |
| European roulette | 2.70% | 37 pockets, one zero |
| Slots | 2%–15% | Studios set RTP between about 85% and 98% |
| Instant games and scratch cards | 3%–10% | RTPs of about 90%–97% |
| American roulette | 5.26% | 38 pockets, two zeros |
| Keno | 20%–35% | 20 numbers drawn from 80, steep paytables |
Slots
The edge on a mobile slot is the gap between 100% and its RTP. The same title can run at different RTP settings at different casinos, so check the help screen at the casino you use, not the studio's headline figure.
Blackjack
Blackjack has the lowest edge of the common games, about 0.5%, but only if you follow basic strategy. Poor decisions push it above 2%. Rules matter too: a table that pays 6:5 for blackjack instead of 3:2 costs you more.
Roulette
The zero pockets are the edge. European roulette has 37 pockets and one zero (2.70%); American roulette has 38 pockets and two zeros (5.26%). On a phone, pick the European wheel whenever both are offered.
Crash games
Most crash games run at 97% to 99% RTP, an edge of 1% to 3%. Many publish a hash so you can verify each round. Cashing out early lowers your swings, not the long-run edge.
Keno
Keno has the highest edge in most lobbies, between 20% and 35% depending on the paytable. It drains a budget fastest.
Instant games
Instant games and scratch cards settle in one tap. With RTPs of 90% to 97%, the edge is 3% to 10%: a scratch card at 95% RTP keeps $5 of every $100 over time.
Blackjack's edge depends on the rules and on the decisions you make. Basic strategy is the set of plays that minimises the casino's advantage on a given rule set. A 6:5 blackjack payout raises the edge compared with a 3:2 payout because the rare blackjack pays less. European roulette's edge is fixed by the single zero. American roulette adds a second zero and the edge rises. Slots do not share one edge. Each title, and sometimes each casino's RTP setting of that title, has its own figure inside the range in the table. Keno's steep paytable is why its edge sits far above table games. Read the help screen of the exact title before you treat a range as your number.
Low-edge games on a small screen
The four lowest-edge games are blackjack, video poker, baccarat on the banker bet and craps on the pass line. They cost the least over time, but they ask more of you on a phone.
- For: smaller long-run losses, clear bet options, and strategy that works well with touch controls.
- Against: strategy charts are hard to read on a small screen, they need more attention than a quick session allows, and lower volatility means smaller swings.
A low house edge reduces the long-run cost per dollar staked. It does not remove short-run swings. Blackjack and video poker need a chart because one wrong hold or one wrong hit changes the edge you actually pay. A phone browser can keep that chart in a second tab. Baccarat on the banker bet asks for less memorisation. The edge there sits in the commission and in the tie bet, so skipping the tie keeps you on the lower figure. The pass line in craps is the low-edge bet on that table. Side bets beside it usually carry a higher edge. Choose the bet with the published lower edge when both sit on the same screen.
Why the edge matters more than the odds
The house edge answers a different question from the odds. Odds describe how often one outcome lands. The house edge describes what the casino keeps from the whole game once every outcome is counted. A player who understands both can judge a game before the first bet is placed. The edge is the number to compare across games, because it is expressed as a share of the stake and so works the same way for a small bet and a large one.
The house edge is an average, not a schedule. It says nothing about the order in which wins and losses arrive. Two players who stake the same amount on the same game can finish a session in very different positions, even though the expected cost is identical. The edge sets the long-run direction of the balance. Variance decides how quickly that direction shows up, and on a phone short sessions make the variance easy to overlook.
Mobile play changes the arithmetic in one important way. The cost of a session is the edge multiplied by the total amount staked, not by the time spent. A player who stakes quickly places more rounds in the same evening, so the same edge produces a larger expected cost. That is why the round rate deserves the same attention as the game choice. Two players on identical games can pay very different totals over a month simply because one of them plays many more rounds.
Reading the edge on a game's help screen
Most licensed studios publish the RTP inside the game's information panel, and that panel is the first place to check before a stake. Look for the stated return figure, the name of the game version and any note about a different setting at a particular casino. The studio figure is a design target. The casino may run the title at a lower or higher setting, so the help screen of the live game is the figure that applies to your money.
Next, check whether the figure refers to the base game or includes bonus features. Some slots state an RTP that includes free spins and a bonus round, while others publish a base figure only. The difference matters because a feature-heavy game can look generous on the headline number and still depend on rare triggers for most of its return. Read the rules text beside the paytable, and note any feature that changes the bet size or the number of lines in play.
Finally, confirm the currency and the stake shown. A game with a published return for a fixed stake may have a minimum bet that changes the cost per round. Keep a short note of the RTP, the version and the stake you plan to use. Comparing that note with the next game you open takes less than a minute, and it keeps the decision based on the edge rather than on how attractive the artwork looks on a small screen.
Common misreadings of the house edge
The first misreading is that a low edge guarantees a win over a short session. It does not. A low edge lowers the expected cost of each stake, but the outcome of a few dozen rounds is still dominated by chance. A player can lose a full budget on a low-edge game in one evening and still have played the game exactly as designed.
The second misreading is that a high-RTP game pays out frequently. The return is an average across a very large number of rounds. A game can return most of the stake over time while paying small wins rarely and large wins seldom. Hit frequency and return are separate properties, and the help screen usually lists both.
The third misreading is that losses can be recovered by changing the bet size after a loss. The edge applies to every stake regardless of its size or the sequence in which stakes are placed. Raising a stake after a loss increases the total amount exposed to the same edge, so it increases the expected cost rather than reducing it.
The fourth misreading treats a bonus as a way to remove the edge. A bonus adds value to the balance, but the wagering terms require that balance to be staked through the same games. Those stakes still pay the edge. The bonus only offsets part of that cost, and it does so only when the terms are completed. Read the wagering section before counting the bonus as value.
Planning a session around the edge
A session plan turns the edge into a budget you can control. Start by deciding the total amount you are prepared to lose for an evening, and treat that amount as the entertainment cost rather than an investment. Then choose the games whose edge fits that plan. A low-edge table game stretches the same budget further than a high-edge keno ticket, so the choice of game changes how long the budget lasts.
Next, set the number of rounds rather than the length of time. Round counts are the direct driver of the total stake, and they are easier to hold steady on a phone than a clock. Turning off turbo and autoplay makes the round count visible. A fixed number of rounds also makes the result easier to review afterwards, because the expected cost can be worked out from the stake and the edge.
Last, stop when the plan ends. The plan should include a clear end point whether you are ahead or behind. Chasing a loss is a decision to raise the total stake against the same edge, and the plan exists to prevent that decision. If the session has ended, close the app rather than opening another game to make up the difference. Reviewing the plan the next day shows which decisions held and which did not.
What the house edge does not tell you
The edge does not show the volatility of a game. Two games with the same edge can deliver very different swings. A high-volatility slot can stay quiet for long stretches and then pay a large win, while a low-volatility game returns smaller amounts more often. The edge is the same in both cases, but the experience and the balance path are not. Choose the volatility that matches your budget, not only the edge.
The edge also does not reflect skill beyond the fixed decisions a game allows. In blackjack the decisions change the edge, and in most slots and roulette the player has no decision that changes it. Where a skill component exists, it works inside the stated edge. It can reduce the cost of a game, but it cannot make a game with a fixed edge pay more than its return.
The edge does not replace the rules of responsible play. Set limits on deposits, session length and losses before the first stake. The rules are the same whatever the edge, because even a low-edge game can cost more than planned over a month of frequent short sessions. Use the deposit and time limits that the casino offers in the account settings, and keep the reality checks switched on where they are available.
Six ways to keep the house edge low on mobile
1. Choose low-edge games
Check the RTP in the game before you play. Prefer slots above 96% RTP, and learn basic strategy before you play blackjack for money. Compare roulette wheels: the European 2.70% costs about half the American 5.26%. Keep keno for small, occasional stakes.
2. Read the rules of each new game
Mobile versions sometimes carry different rules. Check the payout table, how bonus rounds trigger, the minimum bet and any special features, because each of them can move the edge.
3. Keep a strategy chart at hand
Open a basic strategy chart in your browser or a dedicated app and use it while you play blackjack or video poker. Choose a format that reads well on a small screen.
4. Prefer bonuses with low wagering
Aim for wagering of 35x or lower and work out what the playthrough costs before you accept an offer. Our guide to wagering requirements shows the maths.
5. Play in landscape
Turn the phone sideways. You see more of the paytable and game information, and you are less likely to tap a bet by accident.
6. Slow down
Choose games that give you time to decide, and keep autoplay and turbo modes off. Fewer rounds an hour means less money through the edge.
Set a session budget before you start, treat every round as independent and stop at a fixed limit. No betting system beats a positive house edge.
Session length is the lever you control once the game's edge is fixed. Set a stake size and a number of rounds before you open the game. Stop when either limit is reached. The expected cost of the session is the house edge times the total stake, so a smaller stake or fewer rounds lowers that expectation in proportion. Landscape mode shows more of the paytable, which reduces mis-taps that stake a different amount from the one you planned. A strategy chart in a second tab keeps blackjack and video poker on the decision the maths assumes. A bonus with wagering of 35x or lower puts fewer forced stakes through the edge than a higher multiple on the same cash value.
House edge and volatility
The house edge predicts your long-run cost. Volatility describes the short-run swings: how often a game pays and how large the wins are. Two games with the same edge can feel very different over one session.
- Low edge, low volatility: steady results with small, predictable losses.
- Low edge, high volatility: good long-run value with larger swings.
- High edge, low volatility: a slow, steady loss.
- High edge, high volatility: poor value with unpredictable results.
Our guide to volatility in mobile slots and crash games covers the swing side in more detail.
House edge and volatility answer different questions. The house edge is the average share kept over a very large number of rounds. Volatility is the spread of results around that average in a short session. Two slots can share a 4% edge and still pay on different schedules. One returns small amounts often. The other returns larger amounts rarely. Your balance path differs even though the long-run percentage matches. A high-volatility game can finish a short session ahead of or well behind the expected loss. A low-volatility game stays closer to the expected loss on the same stake. Pick the swing size you can sit through, then pick the lower edge inside that swing size.
How bonuses change the edge
A casino bonus adds value, and its wagering requirement takes it back. A $100 bonus at 40x wagering means $4,000 in bets before you can withdraw, and every one of those bets pays the house edge.
Effective edge = base edge − (bonus value ÷ total wagering)
Example: a $50 bonus with 30x wagering means $1,500 in bets. On a game with a 3% edge, 3% − ($50 ÷ $1,500) = 3% − 3.33% = −0.33%. On paper that is a small player advantage while you clear the bonus, but finishing the wagering without losing the balance first is the hard part.
Wagering multiplies the stakes that meet the house edge. A cash bonus is credit you must stake a set number of times before a withdrawal. Each of those stakes is a normal bet on a normal game, so each one pays the game's edge. The bonus value offsets part of that cost. Divide the bonus cash by the total stake the terms require. Subtract that fraction from the game's edge. A negative result means the bonus value exceeds the expected edge cost of the playthrough, on paper, if you finish. Most balances do not finish, because variance can wipe the funds before the counter hits zero. Decline the offer when the required stake is larger than you planned to bet anyway.
Mobile habits that raise the edge you pay
- Autoplay raises the number of rounds you play. Leave it off until you know the game.
- Unfamiliar variants can carry rules with a higher edge. Read the rules first.
- Changed paytables on some mobile versions pay less. Compare before you play.
- Mis-taps place bets you did not intend. Try the controls in demo mode and check the stake before each bet.
