The house edge is the mathematical advantage the casino holds over the player on a given game, expressed as a percentage of each wager. A 2% house edge means the casino expects to keep $2 of every $100 wagered, on average, over the long run.
Also known as: operator margin, casino edge
House edge is the inverse of RTP. A 96% RTP slot has a 4% house edge. Blackjack with optimal strategy can have a house edge as low as 0.5%; American roulette runs about 5.26%; most slots sit between 3% and 6%.
House edge is a long-run statistical expectation. In any given session, results can deviate far from the average — that is what volatility describes. The casino does not need to win every hand; it needs to win on average across millions of hands.
Sportsbook house edge is built into the odds via the "vig" or "juice" — typically 4–5% on standard -110/-110 markets. Same-game parlays and live betting carry significantly higher implied edges.