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How the D’Alembert System Works for Roulette

The D’Alembert System is a negative progression strategy where you increase your bet size after losses. This could help you control your bankroll when playing online roulette.

This guide will discuss how the D’Alembert works and then delve into the pros and cons of following the strategy. We will also provide a hypothetical example of the D’Alembert in action, so read on to decide if this is the right approach for you and see if it can work for the next time you play real money roulette.

What is the D’Alembert System?

Jean-Baptiste le Rond d’Alembert was a famous French mathematician in the 18th century. He believed that a coin flip would be more likely to result in tails if the previous toss resulted in heads.

For that reason, he encouraged gamblers to place larger bets after losing and smaller bets after winning. This belief has since been logically and statistically refuted, and it is now generally known as the gambler’s fallacy.

However, some roulette players still follow the D’Alembert System, a roulette betting strategy, as it appeals to anyone who likes hunting down previous losses.

It applies to even money bets, such as red/black, and it simply requires you to increase your bet amount by one “unit” after you lose and reduce it by one “unit” after you win.

How do you execute the D’Alembert?

Start by determining the size of your base unit. For most players, it will be a percentage of their bankroll, such as 2% or 3%.

As an example, you might have $500 to play with, and you might decide to make 3% of it your base unit. That means you would begin by wagering $15. If you lose, increase it to $30, then $45, then $60, and so on. Then, reduce it by $15 whenever you win.


This chart shows what a hypothetical roulette session might look like for a player following the D’Alembert with a $15 base unit. You will always wager a minimum of $15 if that is your base unit, and you then simply increase it when you lose and decrease it back toward $15 when you win.

Bet AmountOutcomeProfit / Loss

In this example, the player wins eight out of 16 rounds and ends up with a five-unit profit. As you can see, the D’Alembert can be effective at chasing down losses.

However, it does not guarantee success, and you will often struggle to recoup your previous losses if the wheel goes cold.

How does the D’Alembert work for roulette?

The D’Alembert can be applied to any bets that pay out at 1:1, which means you double your money when you win.

There are three suitable options on the roulette table: red/black, high/low, and odd/even.

You can mix it up if you like. For example, you could bet red, then black, followed by odd, and then red again.

However, most players stick to one specific bet when following the D’Alembert. For instance, bet on black with every spin, and increase or decrease your bet size according to the previous result.

You can practice the D’Alembert strategy with online roulette for free. Once you are comfortable you can try your hand with live dealer roulette.

Why you might like the D’Alembert System

  • This system may appeal if you like the idea of chasing down any previous losses in a reasonably aggressive fashion.
  • You may also find it attractive if you find the Martingale System too aggressive.
  • It does not require as large a bankroll as the Martingale System, and you are less likely to run up against table limits.
  • You may also find the D’Alembert appealing if you want to apply greater rigor to your roulette sessions and gain greater control over your bankroll.
  • It might appeal to players who find systems like the Labouchere and the Fibonacci too complex.

Why the D’Alembert might not be for you

  • This system will not appeal to players who want to capitalize upon winning streaks, as you reduce your bet size after a win.
  • It requires a reasonably large bankroll and a table with broad limits, so it will not be suitable for everyone.
  • You can lose track of how much to wager on each spin if you do not remain alert.
  • It is worth remembering that the system creator’s beliefs have been debunked, as the wheel does not remember the previous results and is in no way impacted by them.
  • You can end up needing to place large bets after going on a losing streak, which will not appeal to some players.
  • The D’Alembert cannot eliminate the inherent house edge in roulette, and it does not guarantee success.

Other Roulette Betting Systems

The D’alembert is not the only betting system that you can use when you play roulette. There are several other ways to manage your wagering as you play, including:

The D’Alembert will not help you win at roulette. However, it can help you decide how much to wager on each spin.

It is absolutely legal to use the D’Alembert when playing real money roulette online or visiting a land-based casino. Just make sure you play at a licensed, regulated online casino, and try to find casino games with broad limits in case you embark on a losing streak.

The system gets its name from Parisian mathematician Jean-Baptiste le Rond d’Alembert, who insisted that a gambler was more likely to win after losing the previous bet.

You can easily reverse the D’Alembert System if you want to turn it into a positive progression strategy. Just increase your bet size by one unit after a win and decrease it by one unit after a loss.

The D’Alembert can be a useful system for any players who want to apply greater structure to their roulette sessions. However, the underlying principle has been debunked, as a previous loss does not make future success more likely. There is no way to guarantee success when you play roulette, and the D’Alembert does not cut out the house edge.

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