What Is the House Edge? Explained Simply With Examples

The house edge is the mathematical advantage the casino has on every game. Expressed as a percentage of your bet, it describes how much the operator keeps on average per wager.

Example: A 2.7% house edge means the casino keeps $2.70 of every $100 wagered, long-term. You as a player get back $97.30 on average. That's not a per-round promise — it's the expected value over many bets.

How is the house edge calculated? Simply put: 1 minus payout ratio. In European roulette, a winning straight-up number pays 35 to 1 even though the true odds are 1 in 36 (37 pockets including a single zero). The difference is the house edge: 1/37 = 2.70%.

House edge of the most popular casino games (typical optimal-play values):

• Blackjack with basic strategy: 0.5%

• Baccarat (Banker bet): 1.06%

• French roulette with La Partage: 1.35%

• European roulette: 2.70%

• Video poker (Jacks or Better, optimal): 0.5%

• American roulette (with 0 and 00): 5.26%

• Slot machines: 2% to 15% (varies widely by RTP)

• Keno: 25% to 30%

What does this mean for your strategy? First: prefer games with low house edge — blackjack with basic strategy is mathematically the best classic casino game. Second: no betting system (Martingale, Fibonacci, d'Alembert) can defeat the house edge. They only change your risk profile, not your expected value.

Why don't some players lose then? Short-term variance fluctuates wildly around the expected value. In one session you may win — over thousands of rounds, the house edge necessarily prevails. That's exactly why bankroll management matters more than any betting system.

Important: the house edge isn't a scam — it's the casino's mathematical business model. Understanding it lets you make informed choices and avoid games whose edge is so high that long-term play almost always ends in loss.