D’Alembert Betting System for Roulette

Jean-Baptiste le Rond d'Alembert

The d’Alembert roulette system is named after Jean-Baptiste le Rond d’Alembert, a famous French mathematician of the 18th century. In many ways the d’Alembert system is a less extreme version of the Martingale system, requiring players to increase their bets when they lose and reduce bets when they win.

While this betting system is based on an incorrect argument about coin flipping that d’Alembert made during his lifetime, it can still be a fun and useful roulette system for many players.

How to use the D’Alembert System

In order to use the d’Alembert system you’ll need to first decide on a comfortable betting amount that you’ll like to make during play. A good place to start is the table minimum – for this example we’ll say that’s $10 – though there’s nothing wrong with going higher than that. However, you should definitely pick a number that is only a small fraction of the table maximum if you want to be able to follow the system all the way through. This amount will be referred to as one ‘unit’.

In the d’Alembert system you’ll be making even money bets. Choose the bet of your choice (red or black, odds or evens etc.), and place your initial bet of one unit. If you win, then you can simply place another bet of one unit on your next spin.

If you lose, you’ll want to increase your next bet by another unit (to two units in total). Each time you lose, your betting amount will increase by one unit. Every time you win, you’ll decrease your betting amount by a single unit. Of course, you can never go below one unit even if you go on a long winning streak.

In a pure d’Alembert system there is no maximum bet or number of units you’d be willing to wager (other than those imposed by the table limits). However, it is permissible to set a lower ceiling for yourself if you want to ensure your bets don’t get out of control. For example, you may decide never to wager more than five units no matter what the system says.

Advantages to the D’Alembert System

The biggest advantage to the d’Alembert system is that it’s a slow and steady way of approaching roulette. In comparison to the more famous Martingale system, the risk of catastrophic losses is very low, as you are never doubling your bets. For instance, if you were to lose seven straight bets in the Martingale system you’d lose 123 units (assuming the size of your first bet was one unit). By comparison, those same losses in the d’Alembert system will only cost you 28 units.

Essentially, the d’Alembert system doesn’t have you chase big losses, but rather gives you the chance to win them back over the course of several bets. On the other hand, your wins will normally be just as large as in the Martingale when you do hit a winning streak. This can appeal to players who find that the Martingale is too high-variance and tends to take them out of their comfort zone.

D’Alembert System Drawbacks

We mentioned earlier that this system was based on an incorrect idea that d’Alembert had during his lifetime: the idea that a coin that had come up heads on several flips in a row was now more likely to land on tails on the next spin. Like a coin, a roulette wheel doesn’t actually have a memory of its previous spins. While you’d expect to hit red and black equally often in the long run, that has no effect on the streaks and runs that take place in the short run, and it doesn’t guarantee a perfect balance between the two colors.

In addition, players using the d’Alembert system run the risk of getting into a hole that’s difficult to get out of. Should you lose several bets in a row, it will then take several wins to win your money back. For instance, lose four bets in a row and you’ll be down 10 units. However, winning your next bet will only win five units back. This does contrast with the Martingale, in which a player is guaranteed to show a profit after any bet that results in a win.

Is the D’Alembert System Right for Me?

The d’Alembert system is perfect for players who want some of the fun and excitement that comes with using a Martingale system, but who don’t really want to (or can’t afford to) make the huge bets that are sometimes required in that system.

The same principle of raising bets after a loss is followed. This gives you the chance to win back money after a run of losses, but it doesn’t take that principle to an extreme. If you’d rather see a more graduate shift in your fortunes instead of the slow wins and huge pitfalls of the Martingale, the d’Alembert system for roulette will probably appeal to you.