Martingale calculator
Double after every loss and you recover everything plus one unit — until you run out of money or hit the table limit. This works out exactly how many losses that takes, and how likely you are to see that streak.
48.65% is red on a European wheel. 49.5% is a 2× crash target at a 1% edge.
Chance of ruin in one session
The doubling sequence
Each row is one more loss in a row. Notice how fast the required bet grows and how slowly the accumulated profit does — that asymmetry is the whole trap.
| Loss streak | Next bet | Total risked | Profit if it wins | Chance of getting here |
|---|
Why it feels like it works
Martingale wins most sessions. That is not a flaw in the criticism — it is the mechanism. You collect a small profit nine sessions out of ten, and on the tenth you lose everything you won plus your bankroll. The expected value is unchanged, because it cannot be changed: each bet still carries the same house edge, and adding them together does not create an advantage.
The bankroll line above is the honest version of the system. Doubling from a $1 base, a $1,000 bankroll survives nine consecutive losses and dies on the tenth. At 48.65% win chance a ten-loss streak happens roughly once every 1,700 bets — so in a 500-bet session you are about 25% likely to meet it. Win $250 three sessions running, lose $1,000 on the fourth.
Table limits make it worse, not better. They cap the sequence well before your bankroll does, which is exactly why they exist.
How to use the martingale calculator
- Enter your base bet, bankroll and any table limit.
- Set the win chance of the bet you plan to double on.
- The ruin chance shows how often a session ends with the whole bankroll gone.
Where to test it for free
Run the same sequence on the dice or crash simulator before risking money on it.
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