How House Edge Works

TL;DR — what house edge tells you

House edge is the casino's expected profit as a percentage of the reference amount wagered over the long run. It is not the probability of losing a specific bet, and it is not a deposit fee.

A 2.7% house edge on $1,000 of turnover means an average expected loss of about $27.

Expected loss is not a maximum loss, a budget, or a forecast for one session. For standard roulette, this model uses equal independent bets; other games can have different rules and additional wagering.

House edge, RTP, observed hold, and gross returns

RTP and house edge add to 100% only when they use the same wager denominator and the same assumptions about rules, payouts, and strategy. An RTP of 97.3% does not mean a 97.3% chance of winning.

On $1,000 of recycled turnover at 97.3% RTP, expected gross return is $973. That is not a promised ending bankroll, because the same funds can be wagered repeatedly. The UK Gambling Commission's RTP guide describes RTP as a long-run theoretical return.

Observed hold is the empirical share of turnover retained by an operator over a period. Variance, game mix, and betting volume can make it differ from theoretical house edge.

For slots, RTP and volatility are different measures: equal RTPs can still produce very different win frequencies and swings. See RTP versus slot volatility.

Expected loss is not a suitable budget, a maximum loss, or a point at which a game “should” pay back.

Key terms and denominators

The wager denominator determines what a percentage measures. Use the same denominator before comparing RTP, house edge, or two games.

How to calculate house edge

First calculate the expected value of the bet's net outcome, then express it as a percentage of the selected reference wager.

For a simple two-outcome bet:

Example: betting red on European roulette

A $1 red bet on standard single-zero roulette has 18 winning pockets and 19 losing pockets out of 37.

• Win: 18/37, net result +1
• Loss: 19/37, net result −1
• EV = 18/37 × 1 + 19/37 × (−1) = −1/37
• House edge: 1/37 × 100% = 2.7027%

The win probability is approximately 48.65%. A 1:1 payout means a $1 net profit on a $1 winning bet; the gross payout is 2× the stake because it includes the returned $1 stake.

Not every game fits a two-outcome formula. A push has a net outcome of 0, and games with several payout levels require every outcome. In blackjack, doubles and splits raise all wagers placed; in craps, odds have separate mathematics. A percentage based on the initial wager can therefore differ from one based on all money wagered. General reference calculations are available from Wizard of Odds.

This inline calculator accepts win probability and a net 1:1 payout. Entering 48.65% produces a rounded 2.70%, not the exact 2.7027%; it cannot represent pushes or multiple-payout games.

Casino game house edge comparison

A comparison is useful only when its rules, payout table, and strategy assumptions are stated. The same game name does not guarantee the same edge everywhere.

S17 means the dealer stands on soft 17; DAS means double after split. This is a favourable-rules benchmark, not a figure for every blackjack table: its summary does not supply enough detail, including deck count, to reconstruct a particular table. See Wizard of Odds' baccarat analysis and 9/6 Jacks or Better table.

Fair craps odds have a 0% edge as a supplemental wager, but they do not remove the expected loss of a fixed Pass Line bet; they increase total exposure and turnover. See the Pass Line and odds appendix.

For European roulette with La Partage, even-money bets mathematically have a 1.35% edge when zero returns half the stake. This is conditional on that rule, not a claim about a particular operator.

Slots have no universal house edge. A 96% RTP configuration has a 4% house edge, but that is an example for one configuration, not every slot. In the RTP directory, select the exact title, provider, and version, then confirm RTP in the game's actual rules; stored data may not match an operator's current configuration.

The chart compares only these stated conditions. It does not assign one edge to every blackjack table or slot.

Calculate your own session with the house edge calculator

The calculator converts a percentage into turnover and average expected loss; it does not calculate loss distribution, ruin probability, or a guaranteed session result.

Open the house edge calculator. In the separate preset selector—not the RTP game search—choose “Roulette (European, single zero)”. Then:

1. Set “Bet Size per Round” to 10.
2. Click “By rounds” first.
3. Set “Number of Rounds” to 100.
4. Keep “Rounds per Hour” at 40 as a chosen setting.

Turnover is 10 × 100 = 1,000. The rounded 2.7% setting gives $27 expected loss and $973 expected gross return; the exact European roulette value is about $27.03 at 2.7027%.

House edge calculator settings for European single-zero roulette, stake 10, and 100 rounds

Example settings: 10 per round, 100 rounds, and 40 rounds per hour. Pace is a chosen setting, not a measured player average.

House edge calculator result showing 1,000 turnover and 27 expected loss

This is an average expectation for entered settings, not a forecast of the next session.

For comparison, set each row to a stake of 10 and use the shared 100 rounds. At 2.7%, expected loss is $27; at 5.26%, it is $52.60. The $25.60 difference on equal $1,000 turnover is an expectation difference only.

House edge calculator comparison of European and American roulette at stake 10 and 100 rounds

The extra 00 pocket raises expected loss at equal turnover.

The calculator does not automatically add doubles, splits, side bets, or changing stake sizes, and it does not guarantee a session outcome.

Pace, rules, and strategy

A lower house edge does not always mean a lower hourly expected cost: faster betting can outweigh the percentage difference. These are hypothetical chosen rates, not measured typical speeds.

Progressions, including Martingale, change stake amounts and exposure to large swings; they do not improve payouts or remove underlying house edge. In blackjack, basic strategy and rules for payout, doubling, surrender, and splitting matter. Use blackjack basic strategy flashcards for decision practice. A low edge still means negative expectation.

Set an actual spending limit based on what you can afford to lose, independently of expected loss.

Tools: hourly loss and bankroll erosion illustration

With a $10 stake, 40 bets per hour, and European roulette, expected loss is $10.80 per hour. Over two hours, that is $800 turnover and $21.60 expected loss.

The tool uses the selected stake, edge, rounds, and pace. It gives a deterministic average, not a simulation of random wins and losses.

The bankroll erosion chart is a linear illustration of average expectation at selected percentages. It is not a simulated path, a prediction of time to bankruptcy, or a promise that balance falls in a straight line. Its 8% slot preset is illustrative, not a value for all slots.

Bonuses, casino cards, and terms

Assess a bonus with its wagering requirement, game contribution, maximum bet, expiry, withdrawal cap, and eligibility rules. For example, a $100 bonus with 40× wagering creates $4,000 turnover; at a 4% edge, rough expected wagering cost is $160.

This does not promise profit or a specific promotion result: terms can change eligibility, game contribution, and value. The cards and reviews below are editorial reference material; ratings are editorial, bonus estimates are simplified, and the site may receive affiliate compensation. For further reading, see best-paying online casinos.

Practical takeaway

House edge helps compare the expected cost of games; it does not turn negative expectation into an income method. Check the exact game's rules and RTP, calculate full turnover, consider pace, and set comfortable money and time limits before playing. If you feel pressure to chase losses, take a break instead of increasing stakes.