The one number to know

The house edge is a price tag, not a prediction.

Every casino bet pays a little less than its true odds. That gap is the house edge: the percentage of each bet the casino keeps on average, over a very large number of bets.

Worked example · a single number in roulette

  1. A single-zero wheel has37 pockets
  2. A straight-up bet pays35 to 1
  3. A fair price would be36 to 1
  4. Bet $1 on all 37 pockets: you win onceget back $36
  5. You spent $37, got $36 back−$1 ÷ $37 = 2.70%

Tonight can go either way: short-run results swing far more than the edge. But the edge is what the casino collects across millions of bets, and it's why a longer or faster session costs more.

What does a night cost?

Average cost = bet size × bets per hour × hours × house edge

Average cost of the session$0
Total money wagered$0
House edge used0%
Two sessions in three end between–A normal-distribution estimate of short-term swings.

Paces are typical figures (Wizard of Odds game-speed estimates). Busy tables are slower, empty ones faster. Slot volatility varies widely by game; its swing range here is illustrative.

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