Does the Martingale system work?
No, and the reason is arithmetic rather than opinion. Martingale doubles your stake after every loss so that one win recovers everything, which works on paper because the stake grows as a power of two, and fails in a casino for exactly the same reason. Chasing a single unit through ten consecutive losses means staking 1,023 units and putting 1,024 on the eleventh bet. Two hard limits stop it there. Table maximums truncate the sequence, so the one bet you need is the one you are not allowed to place; and expected value adds up, so a string of negative expectation bets cannot sum to a positive expectation no matter how you size them. On American roulette even money the house edge is 5.263 percent on every single bet, unchanged by what came before, and ten straight losses is a 1 in 613 event, which is rare enough to feel impossible and common enough to happen to somebody every day.
It converts a small, likely win into a rare, catastrophic loss. The average is untouched; only the shape of it changes.
The evidence
| Losses in a row | Next bet | Total staked so far | Chasing |
|---|---|---|---|
| 3 | 8 units | 7 units | 1 unit |
| 6 | 64 units | 63 units | 1 unit |
| 10 | 1,024 units | 1,023 units | 1 unit |
How we know
The numbers above are arithmetic, and we computed them twice in different tools before publishing, because a sum-check is free and a wrong number here would be the kind that reads as authoritative. The stake after n losses is 2 to the power of n, so the running total after ten is 1,023 and the next bet is 1,024. The 5.263 percent American roulette edge is 2 divided by 38, the two green pockets over the full wheel, and it does not move between spins. The regulation makes the independence explicit rather than leaving it as a claim: Nevada Regulation 14.040(6) states that "Gaming devices must not alter any function of the device based on the actual hold percentage", so a game is forbidden from becoming more generous because you are behind. That is the assumption Martingale quietly needs and never states. What is TRUE about it, and worth saying plainly rather than dismissing: Martingale wins small amounts most of the time. That is not an illusion, it is the design. It trades a high probability of a small win for a low probability of a ruinous one, and because the two are balanced against a negative edge, the expected result is worse than flat betting, not better. Anyone who has tried it and come home ahead several times running is describing the system working exactly as the maths predicts, right up until it does not.