D’Alembert Roulette Betting System Explained

D’Alembert Roulette Betting System Explained

Staff Writer
Updated October 30, 2023

D'Alembert Roulette Betting System Explained

The D’Alembert betting system, along with the Reverse D’Alembert or Contra D’Alembert bet system, is a highly ranked betting system oftentimes used in roulette games.

This article aims to explain the nuances of the D’Alembert roulette betting system, as well as show the main differences between the original and the Contra Bet system in roulette. If you want to check out other roulette strategies, visit our guide on the 5 best roulette strategies for playing roulette online and live casinos. 

What Are D’Alembert & Contra D’Alembert Roulette Strategies?

D’Alembert and Reverse D’Alembert are betting systems designed for even-money wagers, which are bets with approximately 50% winning chance.

D’Alembert was invented first – in the 18th century by a French mathematician of the same name. The Reverse D’Alembert system or Contra Bet is a system that works in the exact opposite way of the original system.

Today, both systems are most popular in roulette circles. Players rely on D’Alembert as it is generally considered one of the most successful roulette strategies. Plus, it is also very easy to learn, so it is quite accessible to beginners and inexperienced punters.

In the following sections, we intend to introduce you to both systems and show you how each of them works. We will also give a Compare & Contrast section where we list the biggest differences between the two. If you want to learn how to use the (Reverse) D’Alembert system for online and live roulette, here’s your chance.

D’Alembert Roulette Strategy

D’Alembert system is an even-money betting system commonly applied to roulette games. It is a negative progression system, which means the bets are increased after losing and decreased after every win.

The name comes from Jean-Baptiste le Rond D'Alembert, a French mathematician from the 18th century. D’Alembert, like many scientists of the age, spent a good portion of his life tinkering with mathematical formulas, principles, and laws. His enormous contribution to science includes the now legendary D’Alembert system that is popular at roulette casinos.

For years, the system has been one of the most used systems for betting, often lumped together with Martingale, Labouchere, and Fibonacci. Therefore, like other negative progression systems, D’Alembert has a reverse system that works oppositely.

How D’Alembert Works

D’Alembert system works best for even-money bets in roulette, such as Odd/Even, Red/Black, and High/Low.

The system in itself is remarkably easy to use:

  • After every lossincrease the bet by 1 unit
  • After every windecrease the betby 1 unit

As we said, this is a negative progression system, which means you up the bet when losing, and decrease it when winning.

The crucial part is the betting unit. A betting unit is an amount you are willing to stake as the original bet on the first round. As you progress, you either add or deduce units from the bet total.

If you are new to online roulette and roulette strategies, we recommend starting with a smaller bet as your unit. The easiest way to get used to D’Alembert is to set $1 as your unit. That way, you won’t have a problem keeping track of bet sizes as you play different rounds.

So, here is an example of the D’Alembert roulette system in action ($1 is the unit):

  1. You bet $1 on Red/Black and lose. (+1 unit)
  2. You wager $2. You lose again. (+1 unit)
  3. You wager $3 on the next round. You win. (-1 unit)
  4. Stake $2 on the next round. You win again. (+1 unit)

If you are more of a visual type, we have an image that provides an example of a random round using the D’Alembert roulette betting strategy.

D'Alembert Roulette Example

Reverse D’Alembert Roulette Strategy

The Reverse D’Alembert system is the complete opposite of the system described above. That’s why it is called the Reverse system, or the Contra Bet strategy by players worldwide.

The Reverse D’Alembert is a positively progressive even-money betting system used for online and live casino roulette games.

You increase the bet while winning, and decrease it when losing.

As you can see, the systems are inversed, so the same rules apply but in a counter direction.

At the start of each gaming session, you are also required to come up with a unit that you will refer to throughout the session.

How Reverse D’Alembert Works

This is a positive progression system, so you are not going to decrease the bet after a win, but rather increase it by 1 unit. Likewise, losses warrant a reduction of the wagering amount, rather than growth.

The system is, like its counterpart, a very simple one to remember:

  • After every winincrease the bet by 1 unit
  • After every lossdecrease the betby 1 unit

Of course, units are important. Depending on your betting habits, you can choose to bet something higher or start slower. Whatever your cup of tea, be sure to set up one betting unit before starting with the bets.

Here is what a typical round in online roulette using the Reverse D’Alembert system looks like, with a $1 unit:

  1. You bet $1 on Red/Black and win. (+1 unit)
  2. You wager $2. You lose. (-1 unit)
  3. You wager $1 on the next round. You win. (+1 unit)
  4. Stake $2 on the next round. You win again. (+1 unit)

Following this pattern, the next bet is $3 – and as long as you win, you increase the stake. When you reach a $1 stake and lose, you either reset the process or end the gaming session.

Here is another example of a Contra Bet roulette round.

Reverse D'Alembert Roulette

D’Alembert Versus Reverse D’Alembert System

The two systems might follow the same logic but they offer two completely different gaming experiences.

One of the key differences between the two is the win/loss balance: with Reverse D’Alembert, you are going to lose less money than with straight D’Alembert.

However, to make even a small profit, you need to hit a winning streak, which – if you are familiar with roulette – is a hardly predictable feat. Therefore, you must rely on wins and hits here and there to recuperate what you’ve lost, but there aren’t many chances for big, impressive wins.

Martingale, the roulette strategy, is all for big wins. However, even long dry spells with Martingale in which you risk an exceptionally big amount of money can be saved with just one spin. On the other hand, both D’Alembert systems require longer rounds and at least a few spins to recuperate everything.

Moreover, they are both simple, yes, and easy to learn. Moreover, both D’Alembert systems are on the subtler side, meaning there are no sharp jumps in betting amounts. You go either up or down by 1 unit, making it easier for you to stop and reconsider every step of the way.

Low risk, subtle fluctuations, and simplicity are three powerful advantages for roulette fans. However, the fact that you cannot score big with just a few rounds make it unfavorable for high rollers. On the other hand, if you are a beginner, that is perfect.


And that’s a wrap on our D’Alembert betting system guide – we hope you like what you’ve learned here. As you’ve seen, D’Alembert and Reverse D’Alembert are made for beginners who are not ready to chase big wins, but rather want to enjoy the experience.

The only thing that you do need to take into consideration is the risk of loss chasing. Don’t chase losses. If you see that you are in a dry spell, it’s better to stop and come back later than chase losses and potentially lose the money you are not ready to part with.

Frequently Asked Questions

  • What is the D’Alembert strategy in online roulette?

The D’Alembert Strategy is a betting system used on even bets such as Red/Black, Odd/Even, and High/Low. D’Alembert is quite popular in online roulette, offering you a chance to control the flow of wins and losses so you are not risking as much money as you would with Martingale. This makes it a perfect strategy for beginners.

  • For what kinds of bet can I use D’Alembert?

You can use it for even money bets – the Odd/Even, High/Low, and Red/Black. These bets pay even money, or 1:1.

  • Is D’Alembert better than Contra D’Alembert?

This entirely depends on your playing tastes. Both systems have their perks and disadvantages, so the best way to measure which one is better for you is to define your playing style and then determine which one suits it more.

  • What is negative progression?

Negative progression refers to changes in betting amounts during a gaming session. The betting progression is the antithesis of flat betting, which is the practice of always betting the same amount, regardless of round outcomes. Betting progression meanwhile entails increasing/decreasing the stake according to outcomes. With a positive progression, players increase the bet after they win, and decrease it after they lose. Negative progression works oppositely – you increase the bet after you lose, and decrease it when you win.

  • What other roulette strategies can I try?

You can try a handful of other roulette strategies. If you find negative progression systems interesting, you can give similar systems a go – such as the Martingale, Labouchere, Fibonacci, and the Hollandish. If you like positive progression, you can try the Paroli, Oscar’s Grind, Parlay, and the Reverse Labouchere.



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