The house edge is the structural advantage a casino holds on a particular game. It represents the share of total stakes the operator expects to keep, on average, once prizes are paid out across a very large number of plays. A game returning 97% to players carries a 3% house edge.
This advantage arises from the gap between the true odds of an outcome and the payout offered for it. In European roulette, for example, a single number has one chance in 37 of landing, yet a winning straight-up bet typically pays 35 to 1. That difference between fair odds and actual payout is the mechanism that produces the edge.
Worked example: a player stakes £2,000 in total across a session on a game with a 2% house edge. The long-run model expects the operator to retain around £40 of that turnover. The player’s actual outcome, however, might be a net win or a far larger loss, because the edge only expresses itself reliably over extended play.
- Per-game, per-bet: different wagers within the same game can carry very different edges.
- Strategy-sensitive: in skill-influenced games such as blackjack, the effective edge depends on how optimally the player acts.
- Not a session fee: it is an average, not an amount deducted from each bet.
A frequent misunderstanding is to confuse the house edge with hold percentage. The edge is a theoretical property of the game’s rules; hold is the actual proportion of money an operator keeps in practice, which is affected by how long players recycle their winnings. A low-edge game can still produce a high hold if players keep rebetting.
Exact edges depend on specific rules, pay tables and bet types, all of which vary by operator and jurisdiction, so the same nominal game can carry a different edge in different markets.