How Does a Roulette Wheel Work? Numbers, Layout and Secrets

Look at a real casino roulette wheel up close and try not to want a spin. Polished wood. A gleaming turret. Thirty-seven pockets in red, black and one lonely green. The dealer flicks the ball, it hums around the track, slows, drops, rattles across the metal frets and clicks into place. Four or five seconds of pure mechanics.

Every one of those seconds is engineered. Modern wheels are measured with lasers, fitted with hidden sensors and checked before every shift. It wasn’t always that way — and a few sharp-eyed players got rich because of it.

Here’s the full tour: the numbers, the anatomy, the strange order of the pockets, the table layout, and the story of how a 230-year-old machine became one of the most closely watched objects in any casino.

How Many Numbers Are on a Roulette Wheel?

It depends on the wheel. The quickest trick for knowing how many numbers on roulette wheel variants you’re looking at: count the green pockets.

So when someone asks how many numbers on a roulette wheel, the honest answer is “36, plus the house’s zeros.” The 36 numbers always split evenly: 18 red, 18 black. The zeros are green.

One more fun fact. Add every number from 1 to 36 and you get 666. That’s why roulette has carried the nickname “the devil’s wheel” for well over a century.

The zeros are also where the casino earns its living. Winning bets are paid as if the wheel had only 36 pockets. The extra green pocket gives the house a 2.70% edge on a single-zero wheel. Add a second zero and the edge nearly doubles to 5.26%.

How Does a Roulette Wheel Work? Inside the Machine

A casino wheel has two main parts: a heavy fixed bowl and a spinning rotor that sits inside it. Here’s what does the work.

• The bowl. The solid outer body, usually veneered wood. Its upper rim holds the ball track.
• The ball track. The ball circles here until it loses speed. Top makers no longer trust plain wood for this part. TCS John Huxley uses a solid-stone surface called Velstone, and Cammegh uses its own Garnite. Stone doesn’t wear a groove, and a groove is exactly what can make a wheel predictable.
• The deflectors. Small metal “diamonds” on the slope below the track. They knock the falling ball off course and add randomness.
• The rotor. The spinning disc with the numbered pockets, separated by thin metal dividers called frets.
• The turret and spindle. The shiny handle on top, and the steel shaft the rotor turns on. Underneath sits a precision bearing.

A spin works like this. The dealer turns the rotor one way and launches the ball the opposite way. Opposite directions add chaos. Casino rules take this seriously. In Pennsylvania, for example, if the ball is spun in the same direction as the wheel, the dealer must call “no spin.” The same happens if the ball doesn’t complete four full laps of the track.

And the ball itself? For generations it was carved from ivory, and ivory balls could still be found on casino tables into the 1980s. Today they’re made from Teflon, acetal, nylon or phenolic resin. Players who study wheels say materials behave differently: a bouncier ball skitters more before it settles, and even the “ping” it makes in the pockets sounds different.

Numbers on a Roulette Wheel: Why They’re Not in Order

The table lists 1 to 36 neatly. The wheel does the opposite. That’s deliberate: the roulette wheel numbers are spread so no stretch of the rotor favours one kind of bet.

European wheel (clockwise): 0-32-15-19-4-21-2-25-17-34-6-27-13-36-11-30-8-23-10-5-24-16-33-1-20-14-31-9-22-18-29-7-28-12-35-3-26

American wheel (clockwise): 0-28-9-26-30-11-7-20-32-17-5-22-34-15-3-24-36-13-1-00-27-10-25-29-12-8-19-31-18-6-21-33-16-4-23-35-14-2

The logic behind the numbers on roulette wheel rotors comes down to three rules:

• Red and black always alternate.
• High and low numbers are mixed as evenly as the math allows.
• Odd and even numbers are scattered the same way.

The American wheel adds a neat trick of its own. The 0 and 00 sit directly opposite each other, and so do consecutive numbers: 1 faces 2, 9 faces 10, 27 faces 28.

The European wheel is famous for its named sectors. Voisins du Zéro covers the 17 numbers around zero, from 22 to 25. Tiers du Cylindre is the 12-number arc on the opposite side, from 27 to 33. The remaining 8 numbers are the Orphelins — the “orphans.” You’ll meet all three again on the table.

A Short, Slightly Scandalous History of the Wheel

The Pascal legend

You’ll often read that Blaise Pascal invented roulette while chasing a perpetual motion machine in the 17th century. It’s a lovely story. There’s no solid evidence for it.

Paris, 1796

The first clear descriptions of roulette come from the gambling rooms of the Palais-Royal in Paris in the 1790s. The wheel already looked familiar — and it already had two zeros. Those two pockets were the bank’s entire advantage.

The Blanc brothers cut a zero

In 1843, François and Louis Blanc opened a casino in Bad Homburg, Germany, and took one zero off the wheel. Their pitch was simple: better odds than the competition. It worked. François Blanc later took over the casino in Monte Carlo, and the single-zero wheel became the European standard. Legend says he made a deal with the devil to learn the secrets of roulette — and the 666 total didn’t hurt the rumour.

America goes the other way

Across the Atlantic, early wheels were even greedier. Some carried numbers 1 to 28 plus a 0, a 00 and an American eagle slot — three house pockets. Eventually the format settled at 0, 00 and 1–36, which is why the American wheel still carries the bigger house edge.

When Wheels Went Wrong: Real Biased Wheel Stories

A wheel is a physical object, and physical objects drift. A slightly tilted table, a tired bearing, a loose fret, pockets of uneven depth, wood that warps with humidity, even dust — any of these can make some numbers land more often than they should. One 2012 US patent filing noted estimates that around 30% of roulette wheels show some bias.

Casinos learned this lesson the expensive way.

Joseph Jagger, Monte Carlo

Jagger was a Yorkshire textile man. From the mills, he knew that no spinning wheel is ever perfectly balanced. In the late 19th century (sources give dates from 1873 to 1881), he paid clerks to record results at the Monte Carlo tables. One wheel kept favouring nine numbers: 7, 8, 9, 17, 18, 19, 22, 28 and 29.

He bet on them and won. The casino swapped the wheels around overnight, and Jagger started losing — until he remembered a small scratch on “his” wheel and tracked it down at another table. The casino then began moving the frets. Jagger took the hint and went home with a reputed two million francs, which he put into property in Bradford. Monte Carlo responded with movable partitions and spirit levels.

Hibbs and Walford, Reno and Las Vegas

In 1947, two students — mathematician Albert Hibbs and medical student Roy Walford — went to Reno to hunt for lopsided wheels, then continued in Las Vegas in 1948. Life magazine photographed them drinking milk and counting chips. Estimates of their profit range from $6,500 to $42,000. Either way, it paid for a 40-foot sailboat and more than a year in the Caribbean.

Then they did something bigger. Hibbs became known as “the Voice of JPL” at NASA’s Jet Propulsion Laboratory. Walford became a leading gerontologist.

The García-Pelayo family, Madrid

In 1991, flamenco record producer Gonzalo García-Pelayo brought his family to Casino Gran Madrid and started writing down every spin. A computer did the rest. The data showed which wheels leaned, and the family calculated an edge of around 6% over the house.

The casino tried faster spins and swapped wheels between tables. The family simply recognised the wheels. Total winnings are usually put at around 1.5 million euros. The casino sued for fraud. In 2004, Spain’s Supreme Court ruled that studying a public wheel and betting on its flaws is not cheating.

Epilogue: the Ritz, London, 2004

This one wasn’t a worn wheel. Players at the Ritz used electronic devices to predict where the ball would land and walked away with more than £1 million. It showed where the battle had moved: from wheel defects to wheel physics.

How Modern Roulette Wheels Are Made

Today’s top wheels come from a small group of specialist makers, and the craft is part cabinetmaking, part precision engineering.

Take Cammegh. Bill Cammegh built his first roulette wheel at home in Kent in 1989. By 2001 the company had its first major order: 12 bespoke wheels for Monte Carlo. In 2009 it brought CNC machining in-house for full control over manufacturing. Its wheels use an anti-warp composite structure — a direct answer to the old problem of wood that moves — and a bearing designed to be maintenance-free for life. One model, the Monaco, is styled after the original wheels of the Casino de Monte-Carlo.

Then there’s the jewellery. Buyers choose veneers like walnut burl or mahogany, and turret plating in nickel, gold, brass or rose gold.

TCS John Huxley, the other big name, is known for its patented Starburst separator ring: a fret design built to reduce predictable bounces. Its Saturn wheel can be ordered with anything from one to four zeros.

Before a Wheel Goes Live: Factory and Casino Checks

TCS John Huxley says each of its wheels goes through more than 130 quality checks during production. The final test uses a patented laser measuring device. It captures every area where the ball touches the wheel and checks the tolerances with statistical analysis. The wheel ships with an analytical report.

Then the casino takes over. In several US states, including New Jersey, Pennsylvania, Massachusetts and New York, a supervisor must do the following before a roulette table opens:

• check the table and wheel for magnets or any hidden device;
• confirm the wheel is level and turns freely and evenly;
• make sure every part is secure;
• pass the ball over a magnet or compass to prove it isn’t magnetic.

Adjustments to a wheel can only happen while the table is closed, and in New Jersey a security officer must be present. Every change goes into a signed log.

Every Day on the Floor: How Casinos Watch Their Wheels

Modern wheels monitor themselves. Cammegh introduced the first in-rim sensors in a manual wheel back in 1990. Its current Mercury 360 uses four hidden sensors in the rim. They report the winning number, the speed and direction of both ball and rotor, the game state and alert flags.

The TCS John Huxley Saturn carries a built-in inclinometer to spot tilt. Its patented Drop Zone Detection flags non-random results caused by poor balancing, table movement or tampering. The company’s analysis software tracks bias and game speed in real time and logs every cleaning, levelling and bearing change.

After the Ritz case, makers also started fighting the physics. Cammegh’s Random Rotor Speed system quietly and randomly changes the rotor’s speed at “no more bets,” which makes clocking the wheel far harder. The company says it now accounts for almost a third of the manual wheels it builds.

Live Casino Wheels: The Studio Version

Live roulette runs on the same kind of physical wheels, with a studio built around them. Several cameras cover the wheel and the table. Sensors and optical recognition read the winning number, and a game control unit passes the result to your screen and settles bets.

Some tables drop the dealer entirely. Evolution’s Auto Roulette runs on a fully automated precision wheel. Its Immersive Roulette adds multiple camera angles and a slow-motion replay of the ball settling. Cammegh’s Slingshot 2 automatic wheel is designed to keep the ball in view the whole time.

Retirement: What Happens to an Old Wheel

A wheel that starts to drift isn’t necessarily finished. TCS John Huxley runs a Roulette Technology Centre that refurbishes wheels, including other manufacturers’ models. Every wheel that comes in is checked again with the laser device before it goes back to work.

When a casino closes or replaces its tables, wheels can end up at auction. In one 2019 Australian insurance salvage sale, a mahogany Cammegh Mercury 360 with a listed retail price of AU$9,680 went for AU$900.

Roulette Wheel Layout: How the Table Maps to the Wheel

The wheel is built for randomness. The table is built for convenience. That’s why a roulette wheel and table look so different even though they describe the same 37 or 38 numbers.

A standard roulette wheel table lays out 1 to 36 in three columns of twelve rows, in plain order, with the zero at the head. Inside bets go on the numbers themselves. Outside bets sit around the edge: red or black, odd or even, low or high, dozens and columns.

European roulette wheel layout

One zero at the top of the grid. French tables often add the racetrack, an oval that copies the wheel’s real number order so you can bet on Voisins du Zéro, Tiers and Orphelins in one move. You’ll also see French labels: Rouge and Noir, Pair and Impair, Manque and Passe.

American roulette wheel layout

Two boxes at the top: 0 and 00. The American grid also allows a five-number bet on 0, 00, 1, 2 and 3. It carries the worst house edge on the table, 7.89%, so it’s the one to skip.

Regulators watch the match between wheel and cloth, too. In New Jersey, if a double-zero wheel is used as a single-zero one, the supervisor must confirm the layout and signage fit before the table opens.

Online Roulette: RNG Wheels and Live Tables

Online, the wheel lives in two forms. RNG roulette uses a random number generator tested by independent labs such as GLI, iTech Labs and eCOGRA. A digital wheel has no bearings to wear and no frets to loosen. Live roulette streams a real wheel from a studio, built and checked to the standards above.

Every casino on our list offers both: RNG roulette and live tables running on professional-grade wheels. So the choice comes down to pure pleasure — the studio, the stakes and the style you enjoy most. Browse our Arab casinos and take your pick.