The D’Alembert is a negative progression betting system named after the 18th-century French mathematician Jean le Rond d’Alembert. Players use it on even-money bets, such as red or black in roulette, and some sports bettors apply it too.
First, choose a base unit: a small share of your bankroll, typically no more than 5% and often around 2%. After every loss, the next bet rises by one unit; after every win, it falls by one unit. With a $100 bankroll and a $2 unit, you start at $2, a loss takes you to $4, another loss to $6, and a win then brings you back to $4. Because stakes climb in steps rather than doubling, the swings are gentler than with the Martingale. No staking plan, however, changes the house edge on the bets themselves.
Systems and table limits
System players tend to play long runs of even-money bets, so minimum and maximum stakes decide how far a progression can go. Showing each table’s limits clearly avoids disputes when a sequence reaches the cap.