How casinos make money: a practical guide to house edge and RTP

A casino’s profit model is built on mathematics, not luck. Every wager has an expected value, and the operator earns money by offering games where the long-run average outcome favours the house. Two terms explain most of it: house edge (the percentage advantage built into the rules) and RTP, or return to player (the percentage of stakes paid back over time). Understanding these numbers helps you compare games sensibly and manage bankroll expectations, whether you’re playing roulette, blackjack, or slots.

House edge is the casino’s theoretical margin per bet across a very large number of rounds. If a game has a 2% house edge, the expected loss is £2 per £100 staked over time, though short-term results can swing wildly. RTP is the flip side: an RTP of 98% implies a 2% house edge, but only under the game’s stated rules and correct play where applicable. Variance matters: high-volatility slots can have the same RTP as steadier games yet deliver longer losing streaks. Promotions and loyalty schemes can soften the effective cost, but they rarely overturn the underlying expectation. For a practical benchmark, compare published RTPs and rule variations, and remember that speed of play increases turnover, which increases expected losses. For context on how players assess options, you may see comparisons like duelz casino alongside RTP and bonus terms.

For a personal lens on game maths and risk, many players follow professional poker champion and author Maria Konnikova, who popularised probability thinking for everyday decisions; her updates are on Twitter/X. While poker isn’t a typical house-edge game, her work highlights how discipline, sample size, and decision quality shape outcomes—principles that apply when interpreting RTP and variance. For broader industry context, including regulation and market shifts that influence game design and disclosures, see this reputable coverage: The New York Times.