Roulette House Edge Explained: European vs American
The house edge in roulette is one of the most straightforward examples of casino mathematics. Unlike games where strategy can reduce the advantage, roulette's edge is fixed and unchangeable. Understanding this fundamental concept helps you make informed decisions about which variant to play and what to expect from your gambling sessions.
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What Is the House Edge in Roulette?
The house edge represents the mathematical advantage the casino holds over players in the long run. In roulette, this advantage comes from the green zero (and double zero in American roulette). When the ball lands on zero, all outside bets (red/black, odd/even, high/low) lose, and the casino collects the full stake. This seemingly small detail creates a significant long-term advantage.
House Edge = (Number of zeros / Total numbers) × 100- •House edge is built into the wheel design
- •Cannot be overcome by betting systems
- •Affects every bet type equally in expected value terms
- •Represents average loss per bet over infinite trials
European Roulette: 2.7% House Edge
European roulette features 37 numbers (1-36 plus a single zero). The house edge calculation is simple: with one zero out of 37 numbers, the casino wins 1/37 of all money wagered on even-money bets in the long run. This translates to a 2.70% house edge, meaning for every $100 wagered, the expected loss is $2.70. The single zero design makes European roulette the mathematically superior choice for players.
European House Edge = 1/37 = 2.7027%- •37 total numbers on the wheel
- •Single zero (0) only
- •House edge: 2.70%
- •Best odds for roulette players
- •Standard in European and online casinos
American Roulette: 5.26% House Edge
American roulette adds a double zero (00) to the wheel, creating 38 total numbers. This additional zero nearly doubles the house edge to 5.26%. The extra zero is positioned opposite the single zero on the wheel. While this may seem like a minor change, it significantly impacts your expected losses. For every $100 wagered in American roulette, the expected loss is $5.26—almost twice that of European roulette.
American House Edge = 2/38 = 5.2632%- •38 total numbers on the wheel
- •Both single zero (0) and double zero (00)
- •House edge: 5.26%
- •Nearly double the European house edge
- •Common in US land-based casinos
Does the House Edge Vary by Bet Type?
Interestingly, the house edge remains constant across all bet types in roulette, though the experience differs. Whether you bet on a single number (35:1 payout) or red/black (1:1 payout), the expected value is the same. A straight-up bet on European roulette has the same 2.7% house edge as betting on red. The difference lies in variance—single number bets have high variance (rare big wins), while even-money bets have low variance (frequent small wins).
Expected Value = (Probability of Win × Payout) - 1 = -0.027 (European)- •All bets have identical expected value
- •Straight bets: high variance, rare wins
- •Even-money bets: low variance, frequent wins
- •House edge applies to every spin independently
Key Takeaways
- 1European roulette (single zero) has a 2.7% house edge
- 2American roulette (double zero) has a 5.26% house edge—nearly double
- 3The house edge cannot be beaten by any betting system
- 4All bet types in roulette share the same expected value
- 5Always choose European roulette when available