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.
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.
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.
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.
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.
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.
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.
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.
