The Marks You Are Looking At
When you sit down at a roulette table, the wheel looks like a single spinning object, but it is built from a set of precisely machined parts. The small raised ridges that separate one numbered space from the next are called frets, or sometimes separators. They are not called ticks. The spaces between them are the pockets, and the ball comes to rest in one pocket on every spin.
Understanding the names matters less for conversation and more for reading what you are looking at. The frets are not decorative. They are the physical boundaries that define each numbered compartment, and their placement and height influence how the ball bounces before it settles. A wheel with loose or damaged frets behaves differently from a freshly serviced one, which is why casino staff inspect wheels regularly.
The Parts of a Roulette Wheel
A roulette wheel is a set of concentric parts. The outer rim, sometimes called the ball track, is where the dealer launches the ball. The ball travels around this track in the opposite direction to the spinning wheelhead, then loses speed and drops inward. The frets sit on the wheelhead itself, forming the walls of each pocket. At the centre is the cone, a sloped surface that deflects the ball as it falls.
The numbered pockets are arranged in a fixed sequence. On a European wheel there are 37 pockets, numbered 0 through 36. On an American wheel there are 38, with an additional 00. The frets separate every pocket from its neighbours, and the ball must cross at least one fret before it can settle. That crossing is what creates the bounce and the unpredictability of the final resting place.
| Part | What It Does | What It Looks Like |
|---|---|---|
| Ball track | Outer rim where the ball is launched and travels | Smooth, polished outer ring |
| Frets / separators | Raised metal ridges that divide the pockets | Thin vertical dividers between numbers |
| Pockets | Numbered compartments where the ball lands | Shallow cups, often alternating red and black |
| Cone | Central sloped surface that deflects the falling ball | Domed centre of the wheelhead |
| Wheelhead | The rotating assembly containing pockets and frets | The entire spinning inner section |
Why the Frets Matter to the Game
The frets are not just cosmetic. Their height, spacing and condition affect the physical behaviour of the ball. A ball that strikes a fret at speed can bounce several pockets away, and the pattern of those bounces is part of what makes each spin unpredictable. Casinos keep wheel tolerances tight because a worn fret or a loose pocket can create a bias, and a biased wheel is a maintenance problem, not a player advantage.
None of this changes the mathematics of the game. A European wheel has 37 pockets and a single zero. An American wheel has 38 with a double zero. The extra pocket on the American layout increases the house edge, because the payout for a straight-up win stays the same while the chance of winning falls. The frets do not alter that arithmetic; they only carry the physical process that delivers the outcome.
How a Round Runs from Buy-In to Settlement
You buy in at the table with cash or chips. The dealer gives you roulette chips, which are different from the value chips used at other table games because roulette chips are colour-coded per player so the dealer can tell whose bet is whose. You place bets on the layout until the dealer calls for no more bets. The wheel is already spinning, or the dealer spins it, and the ball is launched in the opposite direction.
When the ball drops into a pocket, the dealer marks the winning number on the layout, clears losing bets first, and then pays winners. Losing chips are swept away before winning bets are paid, which is a sequence worth watching closely if you are new. The dealer then removes the marker and the next round begins. Your roulette chips must be exchanged back for value chips at the table before you leave, because they have no value at the cashier cage.
The Main Bet Types and Their Edges
Every bet on the layout falls into two broad groups: inside bets, which are placed on the numbered grid, and outside bets, which sit around the grid and cover larger sections of the wheel. Inside bets pay more but win less often. Outside bets pay less but cover more numbers. The house edge on a given wheel type is the same for most bets, but the payout odds differ because the probability of winning differs.
The one exception on the American layout is a bet that covers five numbers: 0, 00, 1, 2 and 3. That bet carries a higher house edge than the rest of the table because it pays as if it covered fewer numbers than it does. On both wheel types, the house edge and RTP sum to 100% for the same bet under the same rule set.
| Bet | What It Covers | Payout | How It Compares |
|---|---|---|---|
| Straight-up | One number | 35 to 1 | Highest payout, lowest win frequency |
| Split | Two adjacent numbers | 17 to 1 | Placed on the line between numbers |
| Street | Three numbers in a row | 11 to 1 | Placed at the end of a row |
| Corner | Four numbers meeting at a corner | 8 to 1 | Placed on the shared corner |
| Red / black | 18 numbers of one colour | 1 to 1 | Outside bet, near-even chance |
| Odd / even | 18 numbers of one parity | 1 to 1 | Outside bet, near-even chance |
| Dozen | 12 consecutive numbers | 2 to 1 | Outside bet, one of three blocks |
Where the Wheel Type Changes the Numbers
The difference between European and American wheels is not cosmetic. The European wheel has 37 pockets and a single zero. The American wheel has 38 and a double zero. Because the payouts are the same on both layouts, the extra pocket on the American wheel raises the house edge on every bet except the five-number bet, which is worse again. The wheel type is printed on the layout and visible on the wheel itself, so you can tell what you are playing before you place a chip.
Some tables also offer a rule called la partage or en prison, which applies to even-money outside bets when the ball lands on zero. Under la partage, half the even-money stake is returned. Under en prison, the stake is held for the next spin. These rules change the effective edge on those specific bets, and they are printed in the table rules where they apply. They do not change the edge on inside bets.
Procedural Mistakes New Players Make
The first mistake is touching chips after the dealer has called for no more bets. Once the ball is in motion and the call is made, the layout is closed, and any chip movement will be corrected or refused. The second is mixing up roulette chips with value chips. Roulette chips are only valid at the roulette table, and you must exchange them before leaving. Walking to the cage with them will send you back to the table.
The third mistake is betting late on a number after the ball has already begun to drop. The dealer watches the wheel and the layout, and late bets are returned or disallowed. The fourth is assuming that a number that has not appeared for many spins is due. Each spin is independent, and the wheel has no memory. A number's absence over twenty spins does not change its probability on the next spin.
Reading the Table Before You Sit Down
The table layout carries most of what you need to know. The minimum and maximum bets are printed on a small sign at the table. The wheel type is visible on the wheel itself and usually printed on the layout. The payout for each bet is printed on the layout, and any special rules such as la partage or en prison are noted in the table rules. If you are unsure, ask the dealer before the spin begins. Dealers explain the mechanics, not the odds, but the printed payouts are there to read.
Strategy charts for roulette are not like blackjack basic strategy. Roulette has no decision that changes the house edge, because every bet on the same wheel type carries the same edge except the five-number bet and any rule-modified even-money bets. What you control is bet selection, session length, and how much you stake. Those choices change the pace and the variance of your session, not the built-in edge.
FAQ
What is the difference between a fret and a pocket?
A fret is the raised metal divider between two pockets. A pocket is the numbered compartment where the ball comes to rest. The frets form the walls of the pockets.
Why does the American wheel have a higher house edge?
The American wheel has 38 pockets, including a double zero, while the European wheel has 37 with a single zero. The payouts are the same on both layouts, so the extra pocket reduces the player's chance of winning without changing the payout, which raises the house edge.
Do the frets affect the randomness of the spin?
The frets affect the physical bounce of the ball, but a properly maintained wheel produces outcomes that are independent from spin to spin. The frets are part of the mechanism, not a pattern you can read to predict where the ball will land.
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This article is general information about how these mechanics work. It is not legal advice and not a recommendation to gamble or to use any particular operator. Availability and legality differ by jurisdiction — check the rules that apply where you are.