The European Wheel
European roulette has 37 pockets: 0 through 36. Red and black numbers alternate (mostly). The 0 is green. A bet on red or black has roughly a 48.6% chance of winning.
House edge on even-money bets: 2.7%. This is the most generous roulette game casinos offer.
The American Wheel
American roulette has 38 pockets: 0 through 36 plus 00. Both 0 and 00 are green. Otherwise identical to European roulette.
A bet on red or black now has a 47.4% chance of winning. House edge on even-money bets: 5.26%. The extra 00 roughly doubles the house edge.
If you're playing in Las Vegas or Atlantic City, you're usually playing American roulette. If you're playing online, you might have a choice.
The French Wheel
French roulette is identical to European roulette (same 37 pockets) but with one additional rule: La Partage.
On even-money bets, if 0 hits, you lose half your bet instead of all of it. This reduces the house edge on even-money bets to 1.35%.
French roulette also sometimes offers "En Prison" instead of La Partage. En Prison means your bet is locked when 0 hits. If you win on the next spin, you get your original bet back. Otherwise, the house takes it.
The mathematics of En Prison work out identically to La Partage: roughly 1.35% house edge on even-money bets.
Why These Differences Exist
European casinos developed European and French roulette in more competitive markets. Multiple casinos existed in the same region. They had to offer better odds to attract players.
American casinos, especially in Nevada in the early 1900s, had local monopolies. They could offer worse odds and players would still play, because there was nowhere else to go.
The one extra pocket (00) was an American innovation designed to increase profit. It's pure economics: a 2.7% edge wasn't enough. 5.26% was better.
The Math Over Long Play
On a $100 bet at European roulette, your expected loss is $2.70 per spin. Over 100 spins, that's $270 in expected losses.
At American roulette, your expected loss is $5.26 per spin. Over 100 spins, that's $526 in expected losses.
The difference is significant. American roulette costs roughly twice as much per hour as European roulette, assuming equivalent play volume.
Where to Find Each
European and French roulette are standard in Europe and online casinos. American roulette is standard in physical Las Vegas and Atlantic City casinos.
Some upscale casinos in America offer European roulette, usually at a higher minimum bet to compensate for the lower house edge.
If you're playing online, you can almost always choose. European roulette is the better choice mathematically.
The Visual Difference
The wheels look nearly identical to a casual observer. The difference is one green pocket.
But that one pocket changes everything. Professional players know this. Casual players often don't realize they're playing a worse game until they've lost money.
The best tell is the betting layout. French roulette will have La Partage or En Prison rules printed on the table. American roulette will have 00 marked prominently. European roulette will only have single 0.
The Strategy Implication
If you're playing roulette, play European roulette. If that's not available, play French roulette with La Partage. Avoid American roulette if possible.
The house edge difference is the only strategic consideration. The games are otherwise identical. Your decision is just which tax to pay.
