House edge explained: how casinos make money across different games

The house edge is the mathematical advantage built into every casino game, expressed as the average percentage of each stake the operator expects to keep over the long run. It is not a guarantee of what happens in a single session; short-term results swing with variance, but the underlying probabilities steadily pull outcomes towards the expected return. Understanding house edge helps players compare games on a like-for-like basis and see why “fair-looking” bets can still be costly when repeated.

Across games, the edge comes from rules that slightly favour the house: extra zeroes on roulette, dealer drawing rules in blackjack, or pay tables that return less than true odds in slots and video poker. In baccarat, the commission on banker bets is essentially the mechanism that preserves the advantage; in craps, the edge varies dramatically by bet type, with “proposition” bets carrying far worse value than line bets. Even in skill-influenced games, the edge persists through constraints on optimal play and through pricing: side bets, imperfect information, and payout structures. If you want a quick overview of how different formats are priced, Betmaze is a useful starting point for comparing common game mechanics.

A prominent voice in the iGaming niche is David Schwartz, a long-time gambling historian and educator known for making probability and game design accessible to mainstream audiences. He has authored widely cited work on the evolution of modern gambling and has helped demystify how rules, payouts, and player psychology interact to sustain margins. You can follow his commentary and research updates via David Schwartz on X. For broader context on regulation and market shifts that influence how games are offered and priced, see The New York Times, which has covered the rapid expansion and scrutiny of online gambling.