D'Alembert Roulette System

When it comes to betting, it's important to gamble with a plan in mind. Gambling will always come with its own set of risks, and it's important to stick to a strategy or set of rules to protect your bankroll and make the most of each game.

There are countless betting systems out there, all with unique perks and quirks, but for today we'll focus on the D'Alembert betting system. Developed by the French Mathematician Jean-Baptiste le Rond d'Alembert, this strategy remains popular to this day due to its overall simplicity. So let's take a look at the D’Alembert system up close and find out what it has in store for us. 

It's All About The Even Odds

D'Alembert designed his system based on his theory of mathematical equilibrium. According to this theory, the number of wins will equate to the number of losses in the long run. D’Alembert’s entire betting system is based around the idea that eventually both outcomes will even out, and it's thanks to this stability that a simple set of rules can be applied to the game to maximise profits.

Since this strategy is based on a theoretical 50/50 win to loss ratio, even-money Outside bets are well-suited for this strategy. These bets — Red/Black, Even/Odd, 1-18/19-36 — have a nearly 50% chance of hitting a win. Although the payouts for even-money bets are relatively low (1:1), they are perfect for a multitude of betting strategies out there, including the D'Alembert system. Aside from roulette, this system can be used on any casino game that offers 50/50 outcomes. Craps, for example, offers Pass and Don’t Pass wagers at 1:1. Baccarat’s Player and Banker bets are also noteworthy candidates. 

Keep in mind that the premise behind the D'Alembert system does not account for how long the hypothetical game has to be to reach even results. Winning streaks and losing streaks are as possible in roulette as they are in any game of chance; you always risk losing your bankroll before the results start swinging the other way. When it comes to casino games, theory and reality won't always align.

The Basics Of The D'Alembert Strategy

The D’Alembert strategy is similar to the classic Martingale but is considered to be more consistent and practical, especially when playing with a smaller bankroll. Instead of doubling the wager after a loss, as per the Martingale system, one unit is added to the player’s stake. On a win, the stake is decreased by one unit. This system heavily relies on the equal probability of winning and losing; thus, it is best to stick to even-money bets. This strategy can also be applied in reverse, increasing the wager by one unit on a win and decreasing by one on a loss. 

The D'Alembert system can be easily explained in just four basic rules, and it all boils down to proper bankroll management.

Define Your Unit — The first thing you need to do when applying this strategy is to define your base unit. Ultimately your base unit can be any value you desire, but we strongly recommend sticking to low values in case the amount of bets ends up dramatically increasing during the game. Always keep your bankroll in mind! Regardless of the size of your budget, never try a new strategy with high stakes, it is advisable to look for roulette tables with a low minimum wager or to practice in free demos. You will be able to access the demo upon registration. However, you may be asked for verification before you can access the demo, depending on your jurisdiction.

  1. Stick To It — The next step is as straightforward as it gets: once you join a game, make sure to only bet one base unit. If you chose €1 as your base value, then you will only be increasing/decreasing your wager by €1 for the game’s duration. If you stop and return to play at another time, your initial wager resets to €1. 
  2. Increase On A Loss — The next rule is simply to increase your bet by one base unit every time you lose. This means that if you start with €1 and lose, your next bet will be €2. In the case of another loss, the bet would then rise to €3. This is where the simplicity of the D'Alembert system shines through. Since the basic premise of the whole strategy is that results in 50/50 games will eventually even out, increasing the bet serves to buffer a potential losing streak and break even when it finally ends.
  3. Decrease On A Win — If you win, you'll need to decrease the stake by one base unit. Following the example above, if your wager of €3 won, then your next stake is decreased to €2. The operating principle is the same as with the idea of raising the bet on losses. Losses are inevitable, so it’s important to minimise their impact.

Pros And Cons

As with any betting system, you are going to find similar advantages and disadvantages to the D’Alembert strategy. Let's go over some of its biggest pros and cons in practical usage:


  • By far, the biggest appeal of the D'Alembert system is its simplicity. The rules are easy to pick up and understand.
  • Since the same principles can be applied to any game that offers 50/50 betting odds, this strategy is versatile in its application.
  • Using the D'Alembert strategy encourages players to start with a low base unit, making long-term bankroll management more responsible. 
  • The system is designed to make the most of winning rounds and minimise the damage done by losses.


  • Even if the principle of mathematical equilibrium was foolproof, there's no guarantee how long will it take for a game to even out. Games with 50/50 odds do not have a fixed pattern for how often a given result appears, so it all comes down to chance. 
  • The system is particularly punishing during losing streaks, as you will constantly be increasing your stakes until you win.
  • Earnings are generally low. Since the system is meant to be low-risk and fully based around an idea of stability, it's not designed with large payouts in mind.
  • While the D'Alembert system is appealing by virtue of how approachable it is, it's important to take all factors into account. It is an interesting approach to playing 50/50 games, but there is nothing that inherently prevents extended losing streaks. If you choose to use the D’Alembert system, do so wisely and responsibly. 
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