Roulette’s core idea is old: a ball falls into a numbered wheel and a fixed layout converts the result into payouts. The modern game was shaped less by new betting systems than by changes to the wheel itself—especially the addition, removal and treatment of zero pockets.
Those changes matter because most standard payouts remained constant. Adding another losing zero did not require rewriting every bet. It increased the casino’s advantage across nearly the entire layout.
Early roulette combined several game traditions
Roulette developed in eighteenth-century France from earlier wheel, board and number games. Historical accounts connect its form with games such as biribi, hoca and even-odd wheel devices, although no single invention story explains every feature of the modern table.
The French word roulette means “little wheel.” By the late eighteenth and early nineteenth centuries, recognizable red-and-black layouts with numbered pockets and zero spaces were in use.
The game’s later history is easier to document than its exact birth: European casinos standardized one family of wheels, while American casinos developed another.
Zero created the casino edge
Even-money bets pay 1:1 and cover 18 ordinary numbers. Without zero, 18 red and 18 black pockets would create a fair red-black wager. The zero pocket gives the casino a winning outcome when the ball lands there.
On a single-zero wheel with 37 pockets, the probability of winning red is 18/37 and losing is 19/37. The expected result per unit is:
(18/37 × 1) − (19/37 × 1) = −1/37, or about −2.70%.
The same 2.70% edge applies to most standard single-zero bets because payouts are based on 36 ordinary numbers rather than all 37 pockets.
Double zero defined the American game
American roulette added a 00 pocket, creating 38 total outcomes. Standard payouts did not increase, so the house edge on most wagers became 2/38, or about 5.26%.
A straight-up number still pays 35:1. Fair net odds on one winning pocket out of 38 would be 37:1. The two-unit gap across 38 possible results produces the 5.26% edge.
| Wheel type | Total pockets | Ordinary house edge | Main consequence |
|---|---|---|---|
| Single zero | 37 | 2.70% | European/French mathematical baseline |
| Double zero | 38 | 5.26% | Nearly doubles ordinary expected loss |
| Triple zero | 39 | 7.69% | Further increases cost without changing standard payouts |
| Single zero with la partage | 37 | 1.35% on qualifying even-money bets | Half the stake returned when zero appears |
François and Louis Blanc popularized single-zero roulette
Casino history commonly credits François and Louis Blanc with promoting a single-zero wheel in the nineteenth century, first in German casino operations and later in Monte Carlo. Removing one of the two zero pockets made their game more attractive than competing double-zero versions while preserving a casino edge.
The commercial lesson was important: a lower edge could be used as a competitive feature. European roulette became associated with one zero, while double zero remained common in the United States.
The exact attribution is sometimes simplified in popular histories, but the broader shift toward single-zero continental play is well established.
La partage and en prison softened the zero result
French roulette introduced rules that reduce the cost of zero on even-money bets such as red-black, odd-even and high-low.
Under la partage, the player loses only half the wager when zero appears. This reduces the house edge from 2.70% to about 1.35% on qualifying bets.
Under en prison, the wager can remain “imprisoned” for the next spin. House procedures differ on what happens after another zero or how a released wager is settled, so the exact table rules matter.
Neither rule applies automatically to dozens, columns or straight-up numbers.
The five-number basket became the worst common American bet
American tables often offered a five-number wager covering 0, 00, 1, 2 and 3. It commonly pays 6:1.
The probability of winning is 5/38. The expected result is:
(5/38 × 6) − (33/38 × 1) = −3/38, or −7.89%.
This is worse than the ordinary 5.26% American edge. The bet shows that the number of zero pockets is not the only rule variable; special payouts can create a different cost.
California card roulette changed the mechanism, not the payouts
California historically restricted games in which outcomes were determined directly by a ball and wheel. Casinos developed card-based roulette products in which cards or electronic systems selected the result while the betting layout resembled roulette.
These games can use single-zero, double-zero or proprietary rules. A familiar layout does not guarantee familiar probabilities.
Players must verify how the result is generated, which numbers exist and whether standard roulette payouts apply.
Electronic terminals separated the wheel from the betting position
Stadium and automated roulette let many players wager from terminals connected to one physical or automated wheel. The system can run faster than a conventional table and support smaller minimums.
The mathematical edge comes from the wheel and paytable, not the number of terminals. Faster cycles can increase expected loss per hour even when the percentage is unchanged.
Some systems connect several wheels and automatically assign players to the next spin. This increases pace and can make it harder to verify which wheel and rule set settled a wager.
Online RNG roulette reproduced the table in software
RNG roulette selects a result through approved software and displays a wheel animation. Live roulette streams a physical wheel and dealer. The two formats differ operationally, but a single-zero 35:1 game has the same basic 2.70% edge in either format.
Online software also made unusual variants easy to distribute: multi-wheel games, instant roulette, multipliers, side bets and racetrack interfaces. Each additional feature needs its own rules and expected-value analysis.
A multiplier on selected numbers can be financed by reducing the ordinary straight-up payout or applying the multiplier only under restricted conditions.
Triple-zero roulette increased the edge again
Some modern U.S. casinos introduced triple-zero wheels, often using a third symbol such as 000 or a branded logo. With 39 pockets and standard payouts, the house edge on most bets becomes 3/39, or 7.69%.
The visual difference can be easy to miss when the third zero is represented by a special symbol. The wheel and felt should be inspected before buying chips or opening the online game.
Triple zero does not create new strategy. It creates another casino-winning outcome.
Rule names are not perfectly standardized
“European roulette” usually means single zero. “French roulette” often means single zero with la partage or en prison and a French-language layout. “American roulette” usually means double zero.
Casinos sometimes use these labels loosely. An online game called European Roulette can add side bets, altered limits or special multipliers. The pocket count, payouts and zero rule are more reliable than the title.
Inside and outside bet payouts largely stayed fixed
Standard roulette payouts reflect a 36-number system:
- straight up: 35:1;
- split: 17:1;
- street: 11:1;
- corner: 8:1;
- six line: 5:1;
- dozen or column: 2:1;
- even-money bets: 1:1.
Because those payouts stayed stable, adding zeros raised the house edge. Changing from inside to outside bets alters volatility and hit frequency, not the ordinary edge on the same wheel.
The best historical rule is still the simplest comparison
- Count the zero pockets or equivalent symbols.
- Confirm whether la partage or en prison applies.
- Check special bets and altered straight-up payouts.
- Identify physical, automated or RNG delivery.
- Compare spin speed and total stake.
Roulette’s history shows that one small rule change can have a large economic effect. The wheel may look traditional while an extra zero quietly changes every standard wager.
Related GambleRoad guides explain roulette rules and odds, inside versus outside bets, live versus RNG roulette and roulette strategy limits.