The D’Alembert betting system is a strategy that helps you manage your bankroll when playing blackjack, roulette and other casino games. This D’Alembert betting system guide will explain how the strategy works, how you can apply it to a variety of casino games at top online casinos, and the pros and cons of following it. Read on to become an expert in the D’Alembert system.
How D’Alembert System Works
Jean-Baptiste le Rond D’Alembert was a French mathematician, physicist and philosopher born in Paris back in 1717. He found fame as a leading contributor to the famous Encyclopédie, described as the greatest single enterprise of the Enlightenment, but nowadays he is more famous for his mathematical theory of equilibrium.
He explained that when a coin toss results in tails, it is more likely to land on heads the next time it is tossed. This hypothesis has since been discredited, and it is widely known as the gambler’s fallacy, but the D’Alembert system remains popular among many casino players. It essentially tells you how much you should stake on each spin of the roulette wheel, hand of blackjack or throw of the dice.
The D’Alembert betting system is typically applied to any casino game where there are two potential outcomes – for instance, betting on red or black on the roulette table. The idea is to increase your stake after a loss, and decrease your stake after a win.
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Let’s say you start with a €1,000 bankroll. You can then decide your base unit stake. Some players choose 5% of their bankroll, while others are more conservative and go for 1% or 2%. If you decided to go for 2%, you would place an initial wager of €20. If that bet were to lose, the D’Alembert system would advise you to increase the stake to €40 for your next bet.
If you lost again, you would stake €60 for your third bet.
If you won that bet, you would decrease the stake to €40 for your next bet. The idea is to move up by one base unit whenever you lose, and move down by one base unit whenever you win. If your very first bet is a winner, simply start again by betting one base unit. If at any point you return to one base unit and win, just play again, and only change your stake when you lose.
This table provides an example of how the D’Alembert system can be used in practice:
Wager | Stake | Result of Bet | Win / Loss |
---|---|---|---|
1️⃣ First Bet | €10 | Loss | -€10 |
2️⃣ Second Bet | €20 | Loss | -€30 |
3️⃣ Third Bet | €30 | Win | €0 |
4️⃣ Fourth Bet | €20 | Win | €20 |
5️⃣ Fifth Bet | €10 | Win | €30 |
6️⃣ Sixth Bet | €10 | Loss | €20 |
7️⃣ Seventh Bet | €20 | Loss | €0 |
8️⃣ Eighth Bet | €30 | Win | €30 |
9️⃣ Ninth Bet | €20 | Win | €50 |
🔟 Tenth Bet | €10 | Loss | €40 |
1️⃣1️⃣ Eleventh Bet | €20 | Loss | €20 |
1️⃣2️⃣ Twelfth Bet | €30 | Win | €50 |
In theory, the D’Alembert system is efficient if the number of winning bets works well if the number of winning bets matches or exceeds the number of losing bets. In practice, the house edge on casino games tips the scales against the player, but it is a popular bankroll management tool.
In some ways, it is similar to the Martingale system, as both involve negative progressions whereby the player increases the stake after losing and decreases it after winning. However, the Martingale system is a lot more aggressive, as it involves doubling your stake every time you lose. The D’Alembert system only requires the player to increase the stake by one base unit with every loss, so it is less volatile than the Martingale system.
Some players prefer to go with the reverse D’Alembert system, which you can often read about when searching for the D’Alembert system wiki. This involves increasing your wager by one unit every time you win, and decreasing it by a unit every time you lose.
The D’Alembert system and reverse D’Alembert betting system are popular because they are easy to understand, and help players keep on top of their bankrolls. Our D’Alembert betting system wiki guide explains the pros and cons of using this system, offers tips on how to proceed and provides examples of how it relates to blackjack, roulette, baccarat and craps.
D’Alembert Betting System Pros and Cons
There are several key benefits to using the D’Alembert betting system when playing casino games:
Pros | Cons |
---|---|
👍 This is a pretty low-risk betting strategy, as it carries a significantly lower variance level than other negative progression systems. It does not require steep increases, or decreases, as you always move up and down by just a single unit, so it is not particularly volatile. | 👎 You are unlikely to quickly rack up a large profit and walk away. Some systems involve rapidly scaling up the size of your bets, and while they carry a far higher risk, you can quickly make a large profit and leave the table if the results go your way. The D’Alembert betting system is more cautious. |
👍 The risk of a lengthy losing streak draining your bankroll is a lot lower with the D’Alembert system than with alternative systems, like the Martingale betting system. You would only be pushed to the table limits if you endured a very long losing streak, which is unlikely when betting on binary games with close to even money odds on either outcome. | 👎 A prolonged losing streak can wipe out your bankroll reasonably quickly, as you double your stake every time you lose when using the D’Alembert betting system. |
👍 You can enjoy yourself for a long time at the casino table by following the D’Alembert betting system. Alternative systems carry much higher risk, so you can lose your bankroll quickly if the results go against you. | 👎 It can be difficult to recoup all of your losses if they start to mount up when using the D’Alembert betting system. With the Martingale system, you double your stake with each loss, so you can get back to zero much quicker if the results turn in your favour. |
👍 The D’Alembert betting system helps you think clearly about the size of your bankroll. It prevents you from randomly ramping up or decreasing your stakes without any strategy, and it gives players a greater sense of control while playing their favourite casino games. | 👎 The notion that a coin is more likely to land on heads if it last landed on tails has been disproved. This is now known as the gambler’s fallacy. You do not actually stand a greater chance of success if your last bet lost, so increasing your stake when you lose is not a fail-proof strategy. |
👍 The D’Alembert system is easy to understand. You are unlikely to make miscalculations at the table, as you simply increase or decrease by one unit each time. Alternative systems involve more complex formulae, which increases the likelihood of you growing distracted and accidentally staking the incorrect amount. The simplicity of the D’Alembert betting system allows you to enjoy the game without continually making mental calculations. | 👎 The house edge means that your chances of success are not actually 50/50 each time you place a bet. For example, on a European roulette wheel with 37 pockets, 19 are against you because of the green zero, essentially giving you a 48.6% chance of success each time. Over a prolonged period of time, this means you are unlikely to win the same number of bets as you lose, so it makes it difficult to recover from losses incurred when using the D’Alembert betting system. |
D’Alembert Blackjack Betting System
The D’Alembert system is generally used on binary betting options whereby each potential outcome has almost a 50% chance of success. It is therefore common on side bets when playing roulette, but it can also be used for blackjack. When playing a blackjack hand, there are essentially two outcomes – win or lose – and your chances of success on each hand are close to 50/50, so you can use the D’Alembert betting system at the blackjack table.
The theoretical RTP (return to player) on classic blackjack is 99.41%, which amounts to a pretty low house edge. By contrast, European roulette has an RTP of 97.3%, so blackjack should in theory be better suited to a system that requires the number of winning and losing bets to remain in balance.
The concept is the same. Set aside a bankroll and choose a certain percentage of it as your base unit. Start off by betting one unit per hand. If your bet wins, start again with one unit. If it loses, increase your stake to two units. Increase it by one unit every time you lose, and drop down a unit if you win a hand.

There are no hard and fast rules about what to do with any extra money you make from blackjacks, doubling down and splitting. You might just want to put leave that in your bankroll and continue using the D’Alembert to determine how much to stake on each hand.
The danger with any negative progression system is that you will reach the table limit before you can start to recoup your losses. The D’Alembert system might work best on a table with a relatively low minimum bet and a reasonably high table limit, and you might have a better chance of seeing a balance between winning and losing bets by spending a considerable period of time at the table. Remember to claim any bonuses and loyalty points, as they can eat into that small house edge on blackjack.