Roulette is one game with two different wheels. The European version has 37 pockets and the American version has 38. That one extra pocket changed the game’s commercial trajectory and still shapes how digital roulette is designed and played today.
This piece looks at how the design fork happened, what it means for the game’s mathematics, and how both variants ended up on modern digital platforms.
The Original Wheel: 36 Numbers and One Zero
The modern roulette wheel took its shape in 18th-century France. Blaise Pascal is often credited with developing an early version of the device while working on a perpetual motion machine. The gambling format itself crystallized in Paris during the mid-1700s, with the Blanc brothers establishing the single-zero version in Bad Homburg in 1843.
The original wheel carried 36 numbered pockets plus a single green zero. The zero gave the house its edge. Without it, the game would pay out exactly what the mathematics said it should, which would leave no margin for the operator.
The single-zero design produced a house edge of around 2.7 percent. That was high enough to make the game commercially viable without feeling punitive to players.
The American Fork: Adding the Double Zero
The game crossed the Atlantic during the 19th century and arrived in American gambling houses that wanted a higher house edge. American operators added a second green pocket to the wheel, marked 00, which doubled the house advantage. The American wheel now carried 38 pockets, with the house edge sitting at around 5.26 percent on most bets.
The double-zero decision has shaped American roulette ever since. US casinos run the double-zero version as standard, with single-zero wheels usually confined to higher-stakes rooms. European and UK casinos stuck with the single-zero original, and the single-zero version has remained the default across most of the regulated European gambling market.
European Roulette
Pockets: 37 (1-36 plus one green 0)
House edge: ~2.7% on most bets
Dominant markets: Europe, UK, most international regulated markets
Also known as: Single-zero roulette, French roulette (with la partage rule variant)
American Roulette
Pockets: 38 (1-36 plus 0 and 00)
House edge: ~5.26% on most bets
Dominant markets: United States, Caribbean casino destinations
Also known as: Double-zero roulette
How the Design Fork Played Out in Retro Gaming
The variant split carried over into early video game adaptations. Retro casino simulation titles reflected the geography of their intended audience. The NES-era Vegas Dream defaulted to the double-zero American wheel, while European-developed titles leaned toward the single-zero version.
The Hoyle Casino series on PC and the various Caesars Palace titles across console generations are good reference points for how the two variants appeared on retro platforms. an earlier look at the top video games featuring gambling covers a broader sample of retro titles that featured roulette as part of their casino simulation gameplay.
Arcade cabinets with roulette elements were less common than slot or poker cabinets. When arcade roulette appeared, it typically used simplified wheel designs that abstracted away the variant distinction. The deep variant split mostly stayed in the home computer and console space, where simulation titles had the screen real estate to display a full roulette table layout.
The Variants on Modern Digital Platforms
The design fork has carried into the modern online era. Encyclopedia Britannica’s entry documents both variants as the two recognized standards of the game, with the single-zero version dominant in Europe and the double-zero version dominant in the United States.
Online operators serving different markets carry different default variants. US-facing platforms tend to lead with the double-zero American wheel, and European and UK platforms lead with the single-zero European version. Many online operators carry both, letting players pick based on preference or house-edge awareness.
The UK regulated market strongly favors the European single-zero version. UK platforms typically default to the European wheel, with French roulette (adding the la partage rule, which returns half the stake on even-money bets when zero hits) available as a lower-house-edge option on some platforms.
Operator catalogs vary, and UK roulette games at the likes of Fruity King typically offer both the European and French variants. The dual-variant catalog reflects the UK market’s long preference for the lower-edge single-zero game.
Which Variant Is Better?
From a pure player-value standpoint, the European single-zero variant produces better long-run returns. The 2.7 percent house edge compares favorably against the 5.26 percent on the American wheel. Players who are given the choice between the two will almost always get better value from the European version.
The American version persists because it dominates the home US market, and because many US casinos do not offer the single-zero alternative. The variant split is now a geographic rather than a competitive one. Each wheel dominates its own regional market, with online platforms serving as the main venue where players outside those regions can access either option.
The 18th-century design fork turned out to be unusually durable. The single pocket difference between the two wheels has shaped roulette’s commercial geography for nearly two centuries, and it continues to shape how the game is designed and offered on modern digital platforms.
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Original article by www.oldschoolgamermagazine.com
