Why the house always wins
Roulette payouts are set as if the wheel had only 36 slots — but European wheels have 37 (one zero) and American wheels have 38 (two zeros). That extra slot or two is the casino's built-in profit margin. A straight-up bet pays 35:1, but the true odds of winning are 1-in-37 (European) or 1-in-38 (American). The difference between the true odds and the payout odds is the house edge: 2.70% on European and 5.26% on American roulette.
European vs American: a critical difference
The single extra slot (00) on an American wheel nearly doubles the house edge — from 2.70% to 5.26%. On a $10 bet, this means you expect to lose roughly $0.27 per spin on a European wheel versus $0.53 per spin on an American wheel. Over a session of 200 spins (about 5 hours), that difference compounds to roughly $52 in expected losses. When given a choice, always prefer the European variant.
La Partage: the French advantage
French roulette uses the same single-zero wheel as European roulette, but adds the La Partage rule ("the sharing"). When the ball lands on zero, all even-money bets (Red/Black, Odd/Even, High/Low) receive half their stake back instead of losing the full amount. This cuts the house edge on those bets in half — from 2.70% down to just 1.35%, making French roulette even-money bets among the best value in any casino game. Inside bets are unaffected by La Partage.
The Five Number bet trap
American roulette offers a unique bet covering 0, 00, 1, 2, and 3 — the Five Number bet. It pays 6:1 but has a house edge of 7.89%, the worst bet on any standard roulette variant. The payout structure is mismatched relative to the true odds, making this the one bet you should always avoid.
Betting systems do not work
Strategies like the Martingale (doubling after each loss) do not change the house edge. They shift variance: you win small amounts more often but face occasional catastrophic losses when a losing streak hits table limits or exhausts your bankroll. No betting system can overcome a negative expected value game in the long run. Each spin is an independent event, unaffected by previous outcomes.
Note: All calculations assume a fair, unbiased wheel. Real-world results may vary. This tool is for educational purposes only.
