D'Alembert vs Paroli

Which roulette betting strategy is right for you? Compare these two popular systems side-by-side.

D'Alembert Strategy

Increase bet by one unit after a loss, decrease by one after a win.

moderatesimplenegative progression

Paroli Strategy

Double your bet after each win for a set number of wins, then reset.

conservativesimplepositive progression

10,000 Simulated Sessions Each: D'Alembert vs Paroli

We ran both systems through 10,000 simulated sessions on a European wheel under identical conditions: $1,000 bankroll, stopping at $1,500 (win), $500 (loss), or 500 spins.

Measured over 10,000 sessions	D'Alembert	Paroli
Sessions ended in profit	36.6%	29.4%
Average session result	−$155	−$112
Average spins per session	163	493
Average worst drawdown	−$413	−$232
Best single session	$565	$515
Worst single session	−$610	−$500

In this run, D'Alembert ended more sessions in profit, while Paroli lost less on average — a classic trade-off between win frequency and loss size. Neither beat the house edge.

How D'Alembert sessions ended

Losing sessionsWinning sessions

Lost over $800

Lost $400–$800

63.4%

Lost $100–$400

Lost up to $100

Won up to $100

Won $100–$400

Won $400–$800

36.6%

Won over $800

How Paroli sessions ended

Losing sessionsWinning sessions

Lost over $800

Lost $400–$800

9.5%

Lost $100–$400

43.6%

Lost up to $100

16.8%

Won up to $100

13.7%

Won $100–$400

14.9%

Won $400–$800

1.5%

Won over $800

Methodology: fixed-seed runs from our open simulation engine, using the same settings as the strategy guides and interactive simulators — the numbers here match each system's guide page and can be reproduced there. Both systems lose on average because no betting progression changes the house edge; the comparison shows how differently they get there.