How it's supposed to work
You bet on an even-money outcome, like red at roulette. If you lose, you double. When you finally win, you recover all your losses and gain your starting stake.
The problem: losing streaks grow fast
On European roulette, a red bet loses 19 times out of 37, about 51% of the time, because of the zero. The chance of losing 8 times in a row is only about 0.5% on any given run, but if you repeat the system many times, a long streak becomes very likely. Starting at €5, eight losses in a row means you've lost €1,275, all to try to win €5.
Table limits and bankroll
Tables have maximum bets, and players have limited money. After a few losses, the next doubled bet may be above the limit or more than you can afford. At that point the system simply breaks, and the big loss is locked in.
The house edge doesn't change
Every spin is independent and keeps the same house edge, 2.7% on European roulette. Changing your bet sizes changes how wins and losses are spread out, not the average result. No betting system can turn a negative-edge game into a winning one.
FAQ
Can the Martingale win in the short term?
Yes, it often produces many small wins, but a single long losing streak can wipe them all out and more.
Is there a betting system that beats roulette?
No. Every spin keeps the same house edge, whatever you bet before.
Related guides
Strategy and maths reduce the house edge, but never remove it. 18+, play responsibly.