Roulette is one of the oldest table games in the casino, and it’s still insanely popular. It’s a simple enough, game, too—you have a spinning wheel with numbered slots.

You also have a metal ball which spins around the wheel and drops into one of the slots randomly.

You play roulette in a casino with special chips that are specific to the roulette table. You bet on where the ball will land, and you have a wide variety of options when it comes to that. For example, you can bet on whether the ball lands on odd or even, or you can bet on a specific number.

You can find all kinds of mathematical strategies and systems for winning at roulette, but none of them work in the long run. The game has a built-in mathematical edge that’s impossible to overcome.

The purpose of this post is to explain what roulette is—in detail—so that you can be an educated roulette player before ever making your first bet. I’ll explain the different varieties and variations of the game that are available, too.

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The Basics of How to Play Roulette

Roulette almost looks like the Wheel of Fortune game show. The wheel for the game is horizontal rather than vertical—you’d see a vertical spinning wheel at a carnival or something like that.

But instead of dollar amounts, a roulette wheel has slots where a ball can fall. These slots are numbered 1 through 36, plus there’s a 0 and a 00, for 38 possible outcomes. (This is a description of an American roulette wheel, which is the default here in the USA. I’ll cover other permutations in a later section.)

The dealer at the roulette table is called the croupier. He spins the wheel, clears losing bets off the roulette table, and pays off the winners.

He also exchanges your cash for chips, which should be cashed out at the roulette table rather than at the chip cage.

The betting surface is divided into 2 areas—you can make inside bets or outside bets.

The inside bets are the bets on specific numbers or small subsets of those specific numbers. For example, a bet on a single number, a bet on 2 numbers, or a bet on 3 numbers—any of those would be an inside bet.

Where you place the chip on the betting surface signals to the croupier which bet you’re trying to make.

The outside bets are bets on larger groups of numbers. Since almost half the numbers are black, you can bet on black and win even money. Since almost half the numbers are even, you can bet on even and win even money.

Mathematically speaking, none of these bets are superior to the other. They all carry the same house edge, which is the theoretical amount that the casino expects to win from every bet you place.

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How the House Edge in Roulette Works

The house edge is an average amount that the casino expects to win from each bet. It’s based on a theoretical projection of what’s likely to happen in the long run in the game. It’s based on the fact that you have 38 possible outcomes, each of which is equally likely.

Here’s an example of how to calculate the house edge:

The probability of winning that bet is 1/38. You have 38 possible outcomes, but only 1 of those outcomes is going to make that bet a winner. Another way to look at that probability is to say that your odds of winning are 37 to 1.

Since the odds of winning are less than the payout odds, the house clearly has an edge.

Quantifying that edge mathematically is probably easier than you think, too.

You just look at a theoretically perfect sample of 38 bets, look at your net loss, and average that into how much you’ve lost per bet.

In this example, you’ll win $3500 on 1 of those 38 perfect spins, but you’ll lose $3700 on the other 37 perfect spins. That’s a net loss over 38 spins of $200.

Your average loss PER SPIN, then, is $200 divided by 38. That’s $5.26 per spin, or 5.26%–and that’s the house edge for the game.

As it turns out, the house edge for almost every bet at an American roulette wheel is 5.26%. Only one bet is an exception, and you should never place that bet, because the house edge on that bet is 7.89%.

The example I used of a single number bet is an example of the bet least likely to win at roulette.

But what about the bet that is most likely to be a winner in roulette?

Let’s look at a bet on black.

You have 18 black numbers on the roulette wheel, but you have 20 numbers of other colors. 18 of them are red, and 2 of them (the 0 and the 00) are green.

The bet pays off at even money, so the 18 times you win, you’ll win $1800. On the other 20 spins, you’ll lose $100 each time, or $2000. That’s a net loss over 38 spin of $200.

That’s still $200 divided by 38, or $5.26, or 5.26%.

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What Other Roulette Bets Are Available?

I mentioned that there’s one bet at the roulette table with a 7.89% house edge. I’ll cover it first. It’s called the 5-number bet, or the basket bet. It’s a bet that wins if the ball lands on 0, 00, 1, 2, or 3.

This bet pays off at 6 to 1, so let’s do the math again.

You’ll win 5 times out of 38, and you’ll win $600 each time, for $3000 in winnings.

But you’ll lose 33 times, which means you’ll lose $3300. That’s a $300 net loss.

$300 averaged out over 38 spins is $7.89 per spin, or 7.89%.

This means you should never take this bet. It’s just silly to take a bet where you’re going to lose $7.89 per average instead of a bet where you’re going to lose $5.26 per average.

All the other bets at the roulette table have different payouts, but the house edge for any of them is still 5.26%. Here are the other inside bets that are available, the odds of winning, and the payout for each of them:

- A bet on a single number is a straight up bet. This is a bet that pays off only if the number you chose wins. The odds of winning are 37 to 1, and the payout is 35 to 1. To place this bet, you just place your chip in the center of the number on the table.
- A bet on 2 numbers is a split bet. This is a bet that pays off if 1 of 2 numbers you chose wins. You place this bet by putting your chip on the line between the 2 numbers you’re choosing. The odds of winning are 18 to 1, and the payout is 17 to 1.
- A bet on 3 numbers is a street bet. This is a bet that pays off if 1 of 3 numbers you chose wins. You place this bet by putting your chip on the outside line of a row of 3 numbers. The odds of winning this bet are 12 to 1, and the payout is 11 to 1.
- A bet on 4 numbers is a corner bet. This bet pays off if 1 of 4 numbers you chose wins. You place this bet by putting your chip on the corner of the lines where the 4 numbers intersect. The odds of winning this bet are 9 to 1, and the payout is 8 to 1.
- A bet on 5 numbers is the 5 number bet. I already discussed this at length. Just say no to this bet.
- A bet on 6 numbers is a line bet. It’s a bet that 1 of 6 numbers you chose wins, and you place this bet by putting your chip on the line at the end of 2 rows of 3 numbers, where they intersect. The odds of winning are 6 to 1, and the payout is 5 to 1.

Those are the inside bets. You’ll win these bets less often than you would if you were making outside bets, but the amount you win will also be correspondingly higher.

Here’s a list of the outside bets available, their odds of winning, and the payouts for each:

- A column bet is a bet on the 12 numbers in a single column of the betting surface. The odds of winning this bet are 13 to 6, and the payoff is 2 to 1.
- A dozens bet is another way to bet on 12 numbers, but this one is a bet on the high 1/3, middle 1/3, or the bottom 1/3 of the numbers. The odds of winning this bet are also 13 to 6, but the payoff is 2 to 1.
- A color bet is a bet on red or a bet on black. The odds of winning this bet are 10 to 9, but the payoff is even money.
- An odd or even bet is a bet on whether an odd number or an even number comes up. This one has the same odds and payouts as a color bet. The 0 and the 00 don’t count as odd OR even.
- A low or high bet is a bet on whether the ball will land on 1-18 or 19-36. Same odds of winning and same payout odds.

The question you might ask yourself is whether you should place inside bets or outside bets?

In the long run, it doesn’t matter, because the house has the same edge either way. In the long run, if you keep playing roulette, you’ll eventually lose all your money.

In the short run, though, you should choose an option that suits your playing style and bankroll. I don’t like to play roulette unless I have enough money to place 38 bets, and I don’t usually play longer than that.

If you place 38 bets in an hour on a single number, you might get lucky and see that number come up twice, in which case you’ll probably walk away a winner. You might be unlucky and never see that number come up.

The inside bets obviously win less often, but they pay out more when they do. The outside bets win more often, but the size of your winnings is smaller.

Regardless of which approach you take, keep this in mind:

The numbers I’ve written about so far are based on theoretical, long-term averages. In the short run, like a single session or 2 at the roulette table, you won’t see results that look like that.

You’ll have winning sessions and losing sessions in almost equal amounts if you stick with the even money bets.

The closer you get to an infinite number of trials, the more likely you are to see results that resemble the long term mathematical expectation.

The smaller the number of trials you’re looking at, the more likely you are to see results that don’t resemble the mathematical expectation.

The house edge for all these bets vary with some of the variations that are available.

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Roulette Variations and Variant Games

Until now, I’ve only discussed American roulette.

But that’s not the only variation of roulette available.

This reduces the house edge for the game from 5.26% to 2.70%. One might wonder why the house edge doesn’t just cut in half, since the 0s are responsible for the house edge, and there are half as many of them.

This is because the number of 0s isn’t the only thing that’s changed. The total number of possible outcomes also got smaller.

You only have 37 possible results to divide by instead of 38. This skews the numbers back toward the original house edge.

Here’s an example:

The single number bet on a European roulette wheel has a 1/37 probability of winning, or 36 to 1 odds. The payoff is still 35 to 1.

You’ll lose 36 spins at $100 each, for a total loss of $3600. You’ll still have a single win of $3500. That’s a net loss of $100 instead of $200.

But instead of dividing this by 38 to get an average loss per spin, you’re going to divide it by 37. That’s going to give you an average loss per spin of $2.70, or 2.70%.

European roulette wheels are harder to find in the United States, but they’re out there, especially in Las Vegas and Atlantic City. The betting limits are usually higher on these games, though—you might have to bet $50 per spin minimum to play at such a table.

Now that you know about single zero and double zero roulette, let me warn you about another roulette variation—triple zero roulette.

This game has 39 possible results, 3 of which are 0s. Look at what this does to the house edge:

A single number bet now has a 1/39 chance of winning, or 38 to 1 odds. The payoff is still 35 to 1.

Now you’re looking at $3800 in losses versus $3500 in winnings over 39 spins, which comes to $300 in net losses. Average that out over 39 spins, and you’re losing $7.69 per spin, or 7.69%..

This is a terrible version of roulette that you should avoid on general principle. Usually, casinos will offer these kinds of lousy odds on lower stakes version of their games. The thinking is that they can win more of your money even though you’re risking less money.

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More Variant Roulette Rule

Sometimes when you find a single zero roulette wheel, you’ll also encounter special rules like the “en prison” rule. This rule only applies to even money bets, like red or black. Here’s how it works:

You bet on red. The ball lands on black. In a standard roulette game, you’d immediately lose. But with the en prison rule in effect, your bet gets “put in prison” until the next spin.

If the ball lands on red on this next spin, you get your original bet back with no winnings. If the ball lands on black or green, though, you still lose your bet.

This rule has the effect of reducing the house edge from 2.70% to 1.35%. This makes an even money bet at this kind of roulette table a better bet than the pass line bet in craps, which has a house edge of 1.41%.

Also, since the action at the roulette table is slower than the action at the craps table, you’ll probably lose less money per hour of play.

But the payouts on such a game are correspondingly lower. Also, with a double ball roulette game, the house edge for the various bets is different. They’re not all the same (or almost all the same) as they are in American or European roulette.

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Roulette and Betting Systems Like the Martingale

I don’t want to get into too much detail about the Martingale System or other betting systems similar to it here. I’m planning a lengthy “what is” post on the subject.

But briefly, here’s how it works:

You stick with the even-money bets at the table, and every time you lose, you double the size of your previous bet. This enables you to win back your previous losses and show a one-unit profit.

The problem with this system is that the size of your bets gets too large too fast for this to be a sustainable strategy in the long run.

If you get $5 and lose 8 times in a row, you’re having to place a HUGE bet to keep going—usually a bet that’s bigger than your bankroll or the betting limits at the casino:

- 1. $5
- 2. $10
- 3. $20
- 4. $40
- 5. $80
- 6. $160
- 7. $320
- 8. $640

Most people underestimate the likelihood of long losing streaks like this, but they happen far more often than you’d think.

My advice is to avoid the Martingale System.

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Conclusion

Roulette is a great game, but the house edge for most version of it is higher than I like to face. If you have the bankroll to play in one of the games with a lower house edge, you can get the best of both worlds and enjoy some slow-paced action in front of a spinning wheel.

Do you play roulette? How has your approach to the game changed after reading this post?