As a casino dealer who’s dealt roulette for many years, I’ve seen a few customers whose strategy was to bet on two dozen instead of just one.

For those who don’t know, roulette has 36 numbers (excluding zero). Each dozen covers, respectively, the first, second, and third 12 numbers.

  • First dozen: numbers 1-12
  • Second dozen: numbers 13-24
  • Third dozen: numbers 25-36

This strategy, or system, works exactly the same if you bet on two columns. For instance, first and middle columns.

In terms of play style, betting on two dozen or columns at the same time is definitely more on the conservative side.

This means that although you probably won’t win large amounts, even if you get lucky — you will also minimize losses in case the numbers you bet on don’t come in.

We’ll cover all the advantages and disadvantages of this system in a minute, but now let’s have a look at the actual probabilities.

Chances of winning if you bet on 2 dozen

If you bet on two dozen, you will win approximately two in three times. If the roulette wheel has only one zero, then your chances of winning will be 64.8 percent. If you bet on two dozen and win, you will get paid one and a half times your original bet.

For example, by placing $20 on first dozen and $20 on second dozen, your bet would be $40. Let’s say 17 comes in; you would then lose $20, keep the $20 on second dozen, and get paid $40, for a total of $60.

In this example, assuming you are flat betting, then you are looking at a session in which you’ll profit $20 about two thirds of the time, and lose $40 about a third of the time.

Chances decrease slightly if you play on a double zero (or even worse, triple zero) roulette table.

Betting on 2 dozen: pros & cons

Personally, I’m not a big fan of this system, and wouldn’t use it if I were playing at a casino. Or online, for that matter.

I would always prefer to play a bit less conservatively, e.g. bet on a few numbers straight up, or split, so that the payout would be much bigger if I did win.

But just like any other roulette system, the 2 dozen bet has pros and cons. I can think of the following ones.


  • Easy (no need to calculate anything)
  • Roughly 64.8 chance of winning for each bet
  • Conservative, low risk
  • Outside bets have higher maximums


  • Slow
  • Could get boring quickly
  • Payout is low considering the original bet
  • Outside bets have higher minimums

What if zero comes in?

Some casinos have a rule where if you bet on even chances (red, black, odd, even, low numbers, or high numbers) and zero comes in, then you only lose half of your bet.

This reduces the house edge even further.

Unfortunately, even when this rule is in place, it does not apply to dozens or columns — they are outside bets, but not even chances.

Therefore, if you bet on 2 dozen on roulette and the ball lands on zero, then you will lose your bet.

Roulette two dozen system: example of session

This is an example of what could happen if a player used the two dozen system on roulette. Specifically, betting on first and second dozen.

Completely made up, but hopefully it gives you a better idea.


No roulette system guarantees you’ll win

I’m sure you know this already, but I feel I need to point it out just in case.

No roulette system will ever be profitable in the long run. This is for two main reasons:

  • Roulette has a house edge — relatively low if the wheel has a single zero, and relatively high with a double zero — and this pretty much guarantees that in the long run the player will lose.
  • Even if you were able to exploit a vulnerability of the wheel, and found a system that could indeed guarantee profit in the long run, the casino would ban you. It doesn’t matter if what you’re doing is legal — casinos are a business and cannot lose money.

We’ve all heard of gamblers who won a huge sum on roulette, cashed out, and walked away and never played anymore.

But was it really thanks to a strategy? Or just pure luck? And most importantly, what amount did they start with?

If you put 100k on red, won, and walked away, then your profit would be 100k. But starting with, say, 500, and getting to 100k, is a whole different thing.

Then there are those players who cheated and somehow got away with it. Like the Eastern European gang who won £1.3 million at the Ritz Club in 2004 (I mentioned it here).

Either way, as explained, forget about winning consistently because either your money is eaten by the house edge or you’re practically trying to exploit a vulnerability, which would never be allowed.

I always say the best roulette system is to play for a few minutes, maybe an hour or so, get lucky, and cash out.

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