House Edge

Key Takeaways

• House edge is expected value from the casino's side: the average share of every wager the house keeps. It's the exact complement of RTP: house edge = 100% − RTP.
• The edge comes from payouts set slightly below fair odds, not from rigged outcomes — a fair wheel with unfair prices is the whole business model.
• Edges vary enormously by game and by bet: from ~0.5% (blackjack with basic strategy) to 25%+ (keno, some side bets). Choosing the bet is choosing the price.
• No staking system changes the edge. Betting progressions reshape the distribution of outcomes, never the expectation.
• House edge ≠ hold: re-wagering the same money many times means the house's actual take of a buy-in far exceeds the per-bet edge.

How House Edge Works

Every casino bet has true odds — the real probability of winning — and payout odds — what the house pays when you win. The edge lives in the gap between them.

Roulette is the cleanest demonstration. A European wheel has 37 pockets (0–36). A straight-up number bet wins with probability 1/37 and pays 35:1. The expected value of a $1 bet:

EV = (1/37) × 35 + (36/37) × (−1) = −1/37 ≈ −0.027

Every bet on the layout (straight, split, red/black, dozens) prices out to the same −2.70% — the zero pocket is the house's margin, uniformly applied. Add a second zero (American wheel, 38 pockets, same 35:1 payout) and the edge nearly doubles:

EV = (1/38) × 35 + (37/38) × (−1) = −2/38 ≈ −5.26%

Same game, same payouts, one extra pocket — the edge is pure pricing.

In slots, the edge is embedded in symbol weights and the paytable rather than a visible wheel: the certified RTP (say 96%) directly implies the edge (4%). The mechanism is identical, just hidden inside the math model instead of printed on the felt.

In blackjack, the edge emerges from sequencing: the player must act first and loses busted hands immediately, even if the dealer subsequently busts. Player options (3:2 blackjack payout, doubling, splitting, late surrender) claw most of that back — with perfect basic strategy under liberal rules the residual edge is roughly 0.5%. Rule variations move it materially: 6:5 blackjack payout alone adds about 1.4 percentage points, extra decks and dealer-hits-soft-17 add smaller amounts. Playing by feel instead of the strategy chart typically donates another 1–2 points.

The Numbers: edge by game and bet

Two observations worth internalizing:

1. The spread within one game exceeds the spread between games. Craps pass line is 1.41%; some craps proposition bets exceed 16%. Baccarat banker is 1.06%; the tie is ~14%. Side bets across all table games are systematically priced 5–10× worse than the main bet they sit next to.
2. Skill changes the realized edge only where decisions exist. Blackjack and video poker have decision-dependent edges; roulette, baccarat and slots do not — no choice you make after picking the bet moves the number.

House Edge vs Hold: the multiplier of re-betting

Expected loss compounds through turnover, not deposits:

expected loss = total amount wagered × house edge

A player who buys in for $100 at a 2.70% roulette table doesn't lose $2.70 on average — they typically re-bet winnings repeatedly. Wagering $100 per spin for 50 spins is $5,000 of turnover: expected loss $135, even though the wallet only ever held $100. This is why casino hold (share of buy-in kept) runs far above the per-bet edge, and why wagering requirements measured in turnover are such an effective bonus control.

The same logic gives the honest formula for the cost of any session:

expected cost = average bet × bets per hour × hours × house edge

$2 bets, 400 slot spins/hour, 4% edge → $32/hour expected cost. Whether that's expensive or cheap entertainment is a personal call — but it's a calculable one.

For Players

• Pick low-edge bets and skip side bets. The main-bet/side-bet price gap is the most consistent pattern in casino math.
• Learn basic strategy before playing blackjack — it's a printed chart, legal to use, and worth 1.5+ percentage points versus intuition.
• In roulette, prefer European (single-zero) wheels, and la partage tables if available; never expect a betting system to help. Martingale and friends redistribute when you lose, not whether.
• Use edge to budget, volatility to choose the ride. Edge sets your average hourly cost; variance decides how wildly sessions deviate from it.
• Be suspicious of "no house edge" claims. Legitimate near-zero-edge situations (craps odds bets, promotional overlays) always sit behind a bet or condition that restores the house's margin overall.

For the Industry

• Edge is price positioning. Low-edge flagship games (blackjack, baccarat) function as traffic products with thin per-hand margin and high volume; high-edge games and side bets subsidize them. Managing a floor or a lobby is margin-mix management.
• Transparency is diverging by vertical. Slot RTP disclosure is mandatory in most regulated online markets, while table-game edges are rarely displayed — an asymmetry regulators have started to notice. Operators building trust-first brands increasingly surface effective-price information voluntarily.
• Hold ≠ edge in reporting. Finance teams model theoretical win (turnover × edge) against actual hold; persistent divergence signals data problems, promotional leakage or advantage play, and is a standard audit trigger.
• Game selection interacts with bonus policy. Every wagering requirement is priced against the weighted average edge of eligible games — which is why weighting tables and exclusion lists exist at all.