The D’Alembert betting system is a system where after each loss, one unit is added to the next bet and after each win one is subtracted from the next bet. You start off with something like, 5 or 10 times the minimum bet so that you don’t hit the minimum bet too soon. 10 units is ideal as you have to get 10 wins in a row before you hit the table minimum.

The system is usually played on even money bets. Look at the example below.

Bet Number Units Result Net Profit
1 10 Win +10
2 9 Loss +1
3 10 Loss -9
4 11 Loss -20
5 12 Win -8
6 11 Win +3

In the example above, there are 3 wins and 3 losses. When the number of wins and losses are the same, the net profit is equal to the number of wins. So +3 in this case.

Behaviour of D’Alembert system betting with a £5 stake and £1 increments

The system isn’t great and you’ll lose. Unlike the Martingale, you’ll rarely get ahead and you’ll just lose your money. The longer you play, the bigger your stakes will get and the house edge will get you. Not that I’d recommend Martingale either but at least with Martingale, you can get up a bit before you lose.