What does 'house edge' mean in roulette?

The house edge is the mathematical advantage the casino holds on every bet. In European roulette it is 2.703%: for every €100 wagered on average the casino keeps €2.70. It arises because the wheel has 37 pockets but straight-up bets pay only 35:1. The house edge cannot be overcome by any betting system.

What is a croupier in roulette?

A croupier is the casino employee who operates the roulette table. Duties include spinning the wheel, releasing the ball, announcing 'no more bets', marking the winning number with a dolly, clearing losing bets, and paying out winners. In online live dealer roulette, the croupier is a real person visible via video stream.

What does RTP mean in roulette?

RTP stands for Return to Player — the percentage of all wagered money that is statistically paid back to players over time. European roulette has an RTP of 97.30% (100% minus the 2.703% house edge). French roulette with La Partage has an RTP of 98.65% on even-money bets. American roulette has an RTP of 94.74%.

What is the Gambler's Fallacy in roulette?

The Gambler's Fallacy is the false belief that past outcomes influence future results in an independent random process. For example, believing red is 'due' after 10 consecutive black results. In roulette, every spin is completely independent — the wheel and ball have no memory. The probability of red is always 48.65% regardless of history.

What is a dolly in roulette?

A dolly is a marker placed by the croupier on the winning number on the table layout after each spin. While the dolly is on the table, no bets may be placed, collected, or moved. The dolly is removed only after all losing bets have been cleared and all winning bets have been paid.

Roulette Glossary — Every Term Explained A–Z

Roulette Glossary — A to Z

Over 65 roulette terms defined — from basic gameplay vocabulary to advanced French betting terminology and probability concepts.

A B C D E F G H I J L M N O P R S T V W Z

Action: The total amount of money wagered during a session. A player with €1,000 action has placed €1,000 worth of bets, regardless of wins or losses. Casinos track action to assess player value for comps and VIP programmes.
American Roulette: A roulette variant with 38 pockets — numbers 1–36, a single zero (0), and a double zero (00). The extra pocket increases the house edge to 5.263%, nearly double that of European roulette. Always prefer European or French roulette when available.
Announced Bet: A bet called verbally by the player and immediately placed by the croupier, even before chips are physically placed. Common in French roulette for large wheel-sector bets (Voisins, Tiers, Orphelins). The player is responsible for the chips even if placed on credit.
À Cheval: French for "on horseback". The French term for a Split bet — a chip placed on the line between two adjacent numbers. Pays 17:1.
Ball Track: The outer rim of the roulette wheel where the ball spins before falling into the numbered pockets. The ball track is precisely manufactured to ensure unpredictable ball behaviour. A worn or tilted ball track can theoretically introduce bias.
Bankroll: The total amount of money a player has available to wager. Responsible bankroll management means never gambling with more than you can afford to lose, and setting clear stop-loss and win limits before each session.
Biased Wheel: A physical roulette wheel with a manufacturing defect or wear pattern that causes certain numbers or sections to land more frequently than probability predicts. Genuine biased wheels are extremely rare in modern casinos, which regularly inspect and replace wheels. Bias cannot occur in RNG online roulette.
Black Bet: An even-money outside bet on all 18 black numbers. Win probability: 48.649% (European), payout 1:1. Also called Noir in French roulette.
Call Bet: See Announced Bet. A bet called by name rather than physically placed — e.g., "Voisins du Zéro for €50." Standard on French tables; less common on European tables.
Carré: French for "square". The French term for a Corner bet — a chip at the intersection of four numbers. Pays 8:1. Win probability: 10.811% (European).
Carre: See Carré.
Colonne: French for "column". A Column bet covering 12 numbers in one of three vertical columns on the table layout. Pays 2:1. Win probability: 32.432% (European).
Column Bet: An outside bet covering one of three columns of 12 numbers each. Columns are vertical on the table layout. Pays 2:1. Win probability: 32.432% (European).
Corner Bet: An inside bet covering 4 numbers by placing a chip at their shared corner intersection. Pays 8:1. Win probability: 10.811% (European). Also called Square bet or Carré.
Croupier: The casino staff member who operates the roulette table. Duties: spin the wheel, release the ball, announce "no more bets," place the dolly on the winning number, clear losing bets, and pay winners. In live dealer online roulette, the croupier is a real person filmed via multiple cameras.
D'Alembert System: A betting system where the player increases their bet by one unit after a loss and decreases by one unit after a win. Less aggressive than the Martingale — it does not double the bet. Like all systems, it cannot overcome the house edge; it only changes the distribution of wins and losses.
Devil's Game: A nickname for roulette derived from the fact that the sum of all numbers on a roulette wheel (1+2+3+...+36) equals 666, the biblical "Number of the Beast." The connection is coincidental — the wheel sequence was designed for balance, not numerology.
Dolly: A marker placed by the croupier on the winning number on the table layout after each spin. While the dolly is present, no bets may be placed, moved, or collected. It is removed only after all payouts are complete.
Double Street: See Six Line bet. A bet covering two adjacent rows of three numbers (6 numbers total). Pays 5:1.
Double Zero (00): The second green pocket found only on American roulette wheels. Its addition raises the total pockets from 37 to 38, increasing the house edge from 2.703% to 5.263%. Always avoid American roulette when a European or French table is available.
Douzaine: French for "dozen". A Dozen bet on 12 consecutive numbers (1–12, 13–24, or 25–36). Pays 2:1. Abbreviated P (première), M (moyenne), D (dernière) on French tables.
Dozen Bet: An outside bet on one of three groups of 12 consecutive numbers: 1st dozen (1–12), 2nd dozen (13–24), 3rd dozen (25–36). Pays 2:1. Win probability: 32.432% (European).
En Plein: French for "in full." The French term for a Straight Up bet — a chip on a single number. Pays 35:1. Win probability: 2.703% (European).
En Prison: A French roulette rule: when zero lands on an even-money bet, the bet is "imprisoned" for one more spin. If the next spin wins, the stake is returned (no profit). If it loses, the stake is forfeit. Mathematically equivalent to La Partage — reduces house edge on even-money bets from 2.703% to 1.352%.
European Roulette: The standard, player-friendly roulette variant with 37 pockets (0–36) and a house edge of 2.703%. Always preferred over American roulette. Identical wheel to French roulette but without En Prison or La Partage rules by default.
Even Bet: An even-money outside bet on all even numbers (2, 4, 6 ... 36). Zero is not even. Win probability: 48.649% (European). French name: Pair.
Even Money: A bet that pays 1:1 — you win the same amount as you staked. Even-money bets in roulette include Red/Black, Odd/Even, and Low/High. Despite the name, they do not represent 50/50 odds due to the zero pocket.
Expected Value (EV): The mathematical average outcome of a bet over many repetitions. In European roulette, the EV on a €100 straight-up bet is −€2.70. On any standard bet, EV = −(house edge × stake). No bet has positive EV in standard roulette.
Fibonacci System: A betting system following the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13 ...) — move forward one step after a loss, back two steps after a win. Slower progression than the Martingale. Cannot overcome the house edge; all systems are mathematically equivalent in expected value per euro wagered.
Five-Number Bet: An American roulette inside bet covering 0, 00, 1, 2, and 3. Pays 6:1 with a win probability of 13.158%. The house edge on this specific bet is 7.89% — the worst bet in standard roulette. Avoid completely.
French Roulette: The original roulette variant, using a 37-pocket wheel (identical to European) with En Prison and La Partage rules for even-money bets. House edge on even-money bets: 1.352% — the lowest of any standard casino game. Also features announced bets (Voisins, Tiers, Orphelins).
Gambler's Fallacy: The false belief that past random outcomes influence future results. Example: thinking red is "due" after 10 consecutive black spins. In reality, every roulette spin is completely independent — the wheel has no memory. The probability of red is always 48.649% regardless of history.
Green Numbers: The zero (0) on a European/French wheel, and the zero (0) plus double zero (00) on an American wheel. Green pockets are the source of the house edge — most outside bets lose when green lands.
High Bet: An even-money outside bet on numbers 19–36. Pays 1:1. Win probability: 48.649% (European). French name: Passe.
House Edge: The mathematical percentage of each bet the casino expects to keep over time. European roulette: 2.703%. French roulette (even-money bets with La Partage): 1.352%. American roulette: 5.263%. No betting system can eliminate or reverse the house edge.
Impair: French for "odd." The Odd bet on French roulette tables. All odd numbers (1, 3, 5 ... 35). Pays 1:1.
Inside Bet: A bet placed on the numbered grid of the roulette table layout. Inside bets cover 1–6 numbers and pay higher odds. Types: Straight Up (35:1), Split (17:1), Street (11:1), Corner (8:1), Six Line (5:1), Trio (11:1).
Jeu Zéro: French for "zero game." An announced bet covering the 7 numbers closest to zero on the wheel: 12, 35, 3, 26, 0, 32, 15. Costs 4 chips. A subset of the Voisins du Zéro bet.
La Partage: French for "the sharing." A rule in French (and some European) roulette: when zero lands, even-money bets receive half the stake back immediately. Reduces house edge on even-money bets from 2.703% to 1.352%. Mathematically identical to En Prison.
Labouchère System: A cancellation betting system where the player writes a sequence of numbers and bets the sum of the first and last. A win cancels both ends; a loss adds the bet amount to the end. Requires defining a target profit upfront. Like all systems, it cannot overcome the house edge.
Live Dealer Roulette: Online roulette streamed from a real casino studio with a human croupier operating a physical wheel. Players place bets via software interface; results come from an actual physical ball and wheel. Combines online convenience with the authenticity of land-based play.
Low Bet: An even-money outside bet on numbers 1–18. Pays 1:1. Win probability: 48.649% (European). French name: Manque.
Manque: French for "missed" — referring to numbers that fall short of 19. The French name for the Low bet (1–18). Pays 1:1.
Martingale System: A betting system where the player doubles their bet after every loss, returning to the base bet after a win. The theory: a win eventually recovers all previous losses. In practice: table maximum limits and finite bankrolls prevent infinite doubling. The Martingale does not change the expected loss — only the variance.
Maximum Bet: The highest allowed bet on a roulette table. Casinos set maximums to limit their exposure to large single-spin losses. Typically 500–1000× the table minimum. Maximums apply per bet type, not total.
Minimum Bet: The lowest allowed bet on a roulette table. Inside and outside bets usually have separate minimums. Example: a €5 minimum inside bet table requires at least €5 on each individual inside bet.
Neighbours Bet: A bet on a specific number plus its 2 or more immediate neighbours on the physical wheel (not the table layout). A "5 and the neighbours" bet covers 5 consecutive numbers on the wheel, costing 5 chips (one each). Common on French/live dealer tables with a racetrack.
Noir: French for "black." The Black bet on French roulette tables. All 18 black numbers. Pays 1:1.
No More Bets: The croupier's announcement (or "Rien ne va plus" in French) made after the ball is released, indicating that no further bets may be placed, changed, or collected. Any bets placed after this call are void.
Odd Bet: An even-money outside bet on all odd numbers (1, 3, 5 ... 35). Zero is not odd. Pays 1:1. Win probability: 48.649% (European). French name: Impair.
Orphelins: French for "orphans." An announced bet covering 8 numbers not included in Voisins du Zéro or Tiers du Cylindre: 1, 20, 14, 31, 9, 17, 34, 6. Costs 5 chips (one straight on 1, four splits).
Outside Bet: A bet placed in the outer sections of the roulette table layout, covering large groups of numbers. Lower risk, lower reward. Types: Red/Black (1:1), Odd/Even (1:1), Low/High (1:1), Dozen (2:1), Column (2:1).
Pair: French for "even." The Even bet on French roulette tables. All 18 even numbers (zero excluded). Pays 1:1.
Paroli System: A positive progression betting system (reverse Martingale) — double the bet after each win, return to base after a loss or after three consecutive wins. Aims to capitalise on winning streaks while limiting losses during losing runs. Cannot overcome the house edge.
Passe: French for "passed" — numbers that have passed 18. The French name for the High bet (19–36). Pays 1:1.
Pocket: One of the numbered compartments on the roulette wheel where the ball comes to rest. European wheels have 37 pockets (0–36); American wheels have 38 (0, 00, 1–36). Each pocket is colour-coded: green for zero(s), alternating red and black for 1–36.
Probability: The mathematical likelihood of an event occurring, expressed as a fraction, decimal, or percentage. A single number has a probability of 1/37 = 2.703% in European roulette. Red/Black has a probability of 18/37 = 48.649%. Probability does not change based on past results.
Racetrack: An oval diagram on French and some live dealer roulette tables representing the wheel sequence. Used to place announced bets (Voisins, Tiers, Orphelins, Neighbours) quickly. The racetrack shows numbers in their wheel order, not table order.
Red Bet: An even-money outside bet on all 18 red numbers. Pays 1:1. Win probability: 48.649% (European). French name: Rouge.
Rien ne va plus: French for "nothing goes anymore." The formal announcement equivalent to "no more bets." Once called, all bets are final for that spin.
RNG (Random Number Generator): The software algorithm used in online roulette to determine outcomes, replacing a physical wheel and ball. Certified RNGs are statistically indistinguishable from a physical wheel. They are audited by independent testing laboratories (eCOGRA, iTech Labs, GLI) to verify true randomness.
Rouge: French for "red." The Red bet on French roulette tables. All 18 red numbers. Pays 1:1.
RTP (Return to Player): The percentage of wagered money returned to players over time. RTP = 100% − house edge. European roulette RTP: 97.30%. French roulette (even-money, La Partage): 98.65%. American roulette: 94.74%.
Sector Bet: A bet covering a section of the physical wheel rather than the table layout. Sector bets are placed using a racetrack. Examples: Voisins du Zéro (zero's sector), Tiers du Cylindre (opposite sector). Also called wheel bets or call bets.
Single Zero: The green zero pocket on European and French roulette wheels. Its presence creates the house edge. With a single zero, the house edge is 2.703%. American roulette adds a second zero (double zero, 00), raising the edge to 5.263%.
Six Line Bet: An inside bet covering two adjacent rows of 3 numbers (6 numbers total). Placed on the outer edge between two rows. Pays 5:1. Win probability: 16.216% (European). Also called Double Street or Sixain.
Sixain: The French term for a Six Line bet. Six consecutive numbers in two rows. Pays 5:1.
Snake Bet: A straight-up bet on 12 numbers that form a "snake" pattern on the table layout: 1, 5, 9, 12, 14, 16, 19, 23, 27, 30, 32, 34. All are red numbers. Covers exactly 1/3 of the red numbers. House edge is identical to any other 12-number combination (2.703%).
Split Bet: An inside bet on 2 adjacent numbers, placed on the line between them. Pays 17:1. Win probability: 5.405% (European). French name: À Cheval.
Straight Up Bet: An inside bet on a single number. Pays 35:1. Win probability: 2.703% (European). The highest-paying standard roulette bet. French name: En Plein.
Street Bet: An inside bet covering 3 consecutive numbers in a horizontal row (e.g., 1–2–3, 4–5–6). Placed on the outer edge of the row. Pays 11:1. Win probability: 8.108% (European). French name: Transversale Pleine.
Tiers du Cylindre: French for "thirds of the cylinder." An announced bet covering the 12 numbers on the opposite side of the wheel from zero: 27, 13, 36, 11, 30, 8, 23, 10, 5, 24, 16, 33. Costs 6 chips (6 split bets).
Transversale: French term for a Street bet — three numbers in a horizontal row. Transversale Pleine = street (3 numbers). Transversale Simple or Sixain = six line (6 numbers).
Trio Bet: An inside bet covering 3 numbers including zero: either 0/1/2 or 0/2/3 (European) or 0/1/2, 0/2/3, or 0/00/2 (American). Placed at the junction of the three numbers. Pays 11:1. Only available adjacent to zero.
Variance: A statistical measure of how much results deviate from the expected average. High-variance bets (straight-up) produce large swings in both directions. Low-variance bets (even-money) produce results closer to the expected average. High variance ≠ better odds — the house edge is identical across all standard bets.
Voisins du Zéro: French for "neighbours of zero." An announced bet covering 17 numbers closest to zero on the wheel: 22, 18, 29, 7, 28, 12, 35, 3, 26, 0, 32, 15, 19, 4, 21, 2, 25. Costs 9 chips.
Wheel Bias: A statistical deviation in which certain numbers or sectors appear more frequently than pure probability predicts, due to physical imperfections in the wheel. Historically exploited by advantage players in the 19th and early 20th centuries. Virtually eliminated by modern precision manufacturing and regular casino inspections.
Zero (0): The green pocket that is the sole source of the house edge in European and French roulette. When zero lands, most outside bets lose (exceptions: La Partage and En Prison rules return half or imprison the bet). Zero is neither red nor black, neither odd nor even, neither low nor high.
Zero Game: See Jeu Zéro. An announced bet on the 7 numbers nearest to zero on the wheel.

→ How to play roulette | → French roulette guide | → Complete odds chart