How the D'Alembert works
The D'Alembert is a gentle progression named after the mathematician Jean le Rond d'Alembert. You choose a betting unit, then play an even-money bet (red/black, odd/even, low/high).
After a loss, add one unit to your bet; after a win, remove one unit, never going below the starting bet.
The idea: over time, wins and losses should balance out. When there are as many wins as losses, each win earns one unit. But nothing forces results to balance, and the zero tilts things slightly towards losses.
Strengths
- Very slow progression: only one extra unit per loss.
- Bets stay modest, even after several losses.
- As many wins as losses gives a profit of one unit per win.
How it works in 3 steps
- Betting unitE.g. €10
- Loss?Add one unit
- Win?Remove one unit
Bets, loss after loss:
Progression example (unit: €10)
| Spin | Units | Bet (€) | Result | Net result (€) |
|---|
Tap a result to change it. ✓ = sequence completed.
Random spins use the real odds: 18 chances in 37 of winning.
D'Alembert Calculator
Sequence results
- Next bet
- —
- Total lost
- —
- Remaining bankroll
- —
- Wins in a row to get back in profit
- —
- Max. losses covered
- —
European roulette, even-money bet: 18 chances in 37 of winning and 19 of losing (the zero loses).
Max. losses covered: the number of losses in a row after which you can still place the next bet without exceeding your bankroll or the table limit.
Bets and net result
- Bet per spin
- Net result
- Martingale bet (for comparison)
- Table limit (€500)
Limits and risks
- A long losing run leaves a hole that is hard to fill: each win only pays back part of it.
- Getting back to even can take many more wins than expected.
- The zero makes losses slightly more frequent than wins, so the progression tends to climb.
- Table limits and your bankroll eventually stop the progression.
- The D'Alembert does not remove the casino's mathematical edge (≈ 2.7% on European roulette).
No betting system guarantees a win: every spin is independent of the previous ones.
