Positive stake progression
Contra D’Alembert Roulette: How the Reverse System Works
Contra D’Alembert, also called Reverse D’Alembert, is a stake progression for one even-money roulette bet. Start at 1 unit, add 1 unit after a win and remove 1 unit after a loss.
The stake never drops below 1 unit. The method changes what you bet next, not the wheel odds. A 1-unit win followed by a 2-unit loss leaves the complete result 1 unit down.
Worked version: one fixed even-money bet | start at 1u | win adds 1u | loss removes 1u | floor remains 1u.
See the complete +1 and -1 movement
The example below begins with a 1-unit bet. Two wins raise the next stake to 3 units. The following two losses reduce the next stake back to 1 unit, but the running result finishes 2 units down.
Check the even-money table range first
Contra D’Alembert can keep rising through a winning run, so confirm the minimum and maximum outside-bet stakes before starting.
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The four rules to remember
The standard examples use one fixed even-money bet, such as Red, Black, Odd, Even, High or Low. Do not switch selection after every spin.
Choose the cash value of one unit before the first spin. This is also the minimum stake.
A win at 1u makes the next stake 2u. A win at 2u makes the next stake 3u.
A loss at 3u makes the next stake 2u. A loss at 2u makes the next stake 1u.
If a 1u bet loses, the next stake stays at 1u. The stake cannot fall to zero.
The order of wins and losses changes the result
Counting wins alone is not enough. The same two wins and two losses can finish with a different money result because each spin may use a different stake.
Win, Win, Loss, Loss. The next stake returns to 1u, but the complete result is 2 units down.
Loss, Loss, Win, Win. The next stake is 3u and the complete result is 1 unit up.
One win and one loss can also lose money: win 1u, then lose 2u, and the complete result is -1u. The next bet falls to 1u, but the earlier loss remains part of the balance.
Try the Contra D’Alembert sequence
Press Win or Loss to see the next stake and running result. The tool starts at 1 unit and never reduces the stake below that floor.
Win and loss tester
Default example: one unit equals £1. Change the unit value before entering the first result.
Start with 1 unit. A win makes the next stake 2 units; a loss keeps the next stake at the 1-unit floor.
Recent results: No results yet.
What winning and losing runs actually do
The system moves stake pressure towards winning runs rather than losing runs. That is different from Martingale, but it does not make the complete session safe.
Stakes 1u, 2u, 3u, 4u and 5u win. Complete result: +15u. Next stake: 6u.
Each bet remains 1u. Complete result: -5u. Next stake: 1u.
Results are -1u, -1u and +1u. Complete result: -1u, but the next stake rises to 2u.
The house edge applies to total turnover
On standard European roulette, the theoretical loss on an even-money wager is 2.70% of the total amount staked. It is not 2.70% of the opening balance, and a shorter session does not change the percentage.
| Total amount staked | Theoretical expected loss |
|---|---|
| 10 units | About 0.27 units |
| 50 units | About 1.35 units |
| 100 units | About 2.70 units |
| 500 units | About 13.51 units |
Contra D’Alembert changes the turnover by changing stake size. It does not change the expected percentage attached to each qualifying roulette bet.
European, French and American wheels
The examples above use standard European settlement. Zero loses an even-money bet, so a zero result counts as a loss and the next stake moves down one unit unless it is already at the floor.
| Wheel | Win chance | Zero rule | House edge |
|---|---|---|---|
| European | 18/37 48.65% | Full stake loses | 2.70% |
| French with La Partage | 18/37 48.65% | Half of a qualifying even-money stake is returned | 1.35% |
| American | 18/38 47.37% | 0 and 00 both lose | 5.26% |
Swipe sideways to compare the wheels.
La Partage changes the cash result when zero lands on a qualifying even-money bet. It does not change the +1 and -1 instructions by itself, so the main tester keeps the simpler standard European rule.
Contra D’Alembert compared with similar systems
Contra D’Alembert is not the same as classic D’Alembert or Reverse Martingale. The direction and size of the next stake change are different.
| System | After a win | After a loss | Where stake pressure builds |
|---|---|---|---|
| Contra D’Alembert | Add 1 unit | Remove 1 unit, floor 1u | Winning runs |
| Classic D’Alembert | Remove 1 unit | Add 1 unit | Losing runs |
| Reverse Martingale | Usually multiply the stake | Reset to the base stake | Winning runs, faster growth |
| Ascot | Move up a chosen ladder | Move down the ladder | Depends on the ladder and result order |
Swipe sideways to compare the systems.
Contra avoids Martingale’s loss-side doubling, but that does not make it automatically safe. Its stake can continue rising during a winning run, and an unfavourable order of results can place losses on the larger bets.
Method used for the examples
Calculation assumptions
- Bet type: one fixed even-money selection paying 1:1.
- Starting stake and minimum stake: 1 unit.
- Win: add exactly 1 unit to the next stake.
- Loss: remove exactly 1 unit, without dropping below 1 unit.
- Standard examples use European roulette, where zero loses.
- No automatic five-win reset or fixed profit target is assumed.
- Running results are net of every completed stake.
Related RouletteUK guides
Contra D’Alembert roulette FAQs
What is the Contra D’Alembert roulette system?
It is a positive stake progression used with one even-money bet. Start at 1 unit, add 1 unit after a win and remove 1 unit after a loss, without dropping below 1 unit.
Is Contra D’Alembert the same as Reverse D’Alembert?
Yes. Both names normally describe the reversed movement of classic D’Alembert: the stake rises after a win and falls after a loss.
What happens if the first 1-unit bet loses?
The next stake remains 1 unit because the system has a one-unit floor. Further losses at the floor also use a 1-unit next stake.
Can equal numbers of wins and losses still lose money?
Yes. Win 1u and then lose 2u, and the complete result is -1u. With this system, the result order decides which stakes win and which stakes lose.
When should the progression reset?
The basic +1 and -1 rules do not provide one universal reset point. Some versions reset at a chosen result or after a fixed run. This guide leaves reset as a manual decision and does not present a profit target as a mathematical rule.
Does Contra D’Alembert beat the house edge or make Martingale safe?
No. It changes stake movement but not roulette probabilities or payouts. It avoids loss-side doubling, but larger bets can still lose and cumulative losses can still grow. Standard European even-money bets retain a 2.70% house edge.
Use the sequence to record stakes, not to chase a result
Choose the cash value of one unit before starting and do not increase that base value to recover losses. The tester is most useful for seeing how quickly turnover and the running result can change even when the next stake falls.
Practise the movement on a free roulette game before using real money. 18+. Roulette is a negative-expectation game. Play only with money you can afford to lose.