A game of chance, not a puzzle to solve
Roulette is a game of chance with a built-in house edge. No strategy, system, pattern or timing changes the odds in the player’s favor over time, and most players lose money over time. Nobody should gamble money they cannot afford to lose. This guide explains the mechanics so the table makes sense, not as a route to winning. If gambling is causing you worry, a local support service can help.
The wheel
A roulette wheel is a shallow bowl with a rotating inner disc. The rim of the disc is divided into numbered pockets, each just big enough to hold the ball. On the most common international design, called a single-zero or European wheel, there are 37 pockets: the numbers 1 to 36 and a single 0. On the American design there are 38, because a second green pocket marked 00 is added.
Eighteen of the numbers from 1 to 36 are red and eighteen are black. The zero pockets are green and are neither red nor black, neither odd nor even, and neither high nor low. That detail is where the casino’s advantage comes from, as later sections show.
The numbers are not placed in numerical order around the wheel. Instead they are arranged so that colors alternate and high and low numbers are spread around. Because of this arrangement, numbers that sit next to each other on the wheel are generally far apart on the betting layout, and the reverse.
The betting layout
The betting surface, often called the cloth or layout, is a grid. The numbers 1 to 36 sit in three columns of twelve, and the zero (or zeros) sit at the top of the grid. Around the numbers are boxes for the groups of bets that need no particular number.
Bets fall into two broad families:
- Inside bets are placed on the numbers themselves, either on one number or on small groups of neighboring numbers, by placing chips on or across the lines between them.
- Outside bets are placed in the boxes around the grid and cover large groups, such as red or black, odd or even, low or high, the three dozens and the three columns.
The details of both families, including how many pockets each covers, are set out in the explanation of inside bets and outside bets. The short version is that the more pockets a bet covers, the more often it wins and the less it pays.
Standard payouts
Payouts are quoted as “to 1”. A bet that pays 35 to 1 returns 35 units of profit for each unit staked, plus the original stake. On a single-zero wheel the usual payouts are:
| Bet | Pockets covered | Pays |
|---|---|---|
| Single number | 1 | 35 to 1 |
| Two adjacent numbers | 2 | 17 to 1 |
| Three numbers in a row | 3 | 11 to 1 |
| Four numbers in a square | 4 | 8 to 1 |
| Six numbers in two rows | 6 | 5 to 1 |
| A dozen or a column | 12 | 2 to 1 |
| Red/black, odd/even, low/high | 18 | 1 to 1 |
The gap between these payouts and the real chances is the subject of payout ratios, but one number is worth noting now. A single number wins on 1 pocket out of 37, so the true odds against are 36 to 1. The casino pays 35 to 1. That one unit difference is the house edge in action.
The sequence of a round
A round follows a fixed order, and the rules are the same whether it happens at a physical table or in a streamed live dealer games format:
- Players place chips on the layout while betting is open.
- The dealer spins the wheel in one direction and launches the ball in the opposite direction around the rim.
- As the ball slows, the dealer announces that no more bets are accepted. Chips cannot be added or moved after that call.
- The ball drops from the rim, bounces among the pockets and settles in one.
- The dealer announces the winning number and marks it on the layout, usually with a marker.
- Losing chips are collected, winning bets are paid, and then the marker is removed so the next round can start.
In electronic versions, software built on random number generators picks the result and the animation follows it, so the wheel is a display rather than the source of randomness.
Where the house edge comes from
On a single-zero wheel there are 37 equally likely pockets, but the payouts are calculated as though there were 36. Every standard bet therefore loses a little on average. The long-run average loss is 1 unit in every 37 staked, or about 2.7 percent, on a single-zero wheel. With 38 pockets the same payouts leave a house edge of two parts in 38, about 5.26 percent. This is the number the casino relies on, and the law of large numbers explains why that average becomes dependable across many thousands of spins even though a single spin is unpredictable.
A hypothetical example: if someone staked 10 units on a single number for each of 37 spins, they would stake 370 units in all. On average that would return 360 units, a loss of 10 units, or 1 unit in 37 staked. In any actual session the result can be far better or far worse than the average, which is why short sessions feel so different from the long-run figure.
What the layout does not do
Because the arrangement of the wheel and the layout is fixed, it can look as if it hides some structure to exploit. It does not. Each spin is an independent event, and the ball has no memory of earlier results. Rituals, lucky numbers and gambling superstitions do not alter the outcome. Betting patterns do not either; each is simply a different mix of bets that all carry the same edge, and so betting systems cannot change the odds.
Reading the rules at a particular table
Tables differ in small ways that affect the cost of playing: whether the wheel has one zero or two, whether partial-return rules apply to even-money bets, which minimum and maximum bets are posted, and whether extra bets or special formats are offered. Checking those rules before playing is worth the minute it takes, and setting an entertainment budget in advance, as the cost of an evening rather than a way to earn money, is a sensible habit.