Why doubling stays under 50%
Say you start with 100 and stop at 200 or at 0. When you finish, your average holding is 200 × (chance of reaching 200). Each bet loses on average, so that average must be below 100, which means the chance of reaching 200 is below 50%. A 5x goal is below 20%, a 10x goal below 10%, whatever system you use.
Chance of reaching the goal
| Approach (bankroll 100, European wheel) | Goal | Reached | Bust |
|---|---|---|---|
| Martingale, base bet 1 | 200 (2x) | about 43% | about 57% |
| Martingale, base bet 10 | 200 (2x) | about 47% | about 53% |
| Everything on red, once | 200 (2x) | about 48.6% | about 51.4% |
| Martingale, base bet 1 | 500 (5x) | about 13% | about 87% |
Simulation figures use the app’s rules (always bet red, double after a loss, reset after a win), run thousands of times. Re-running shifts them by a point or two.
Oddly, the fewer and bigger the bets, the less the house edge grinds you down and the closer you get to the cap. You still never pass 50%, and the odds fall fast as the goal grows.
Why few people stop
- Those who hit the goal often feel lucky and raise it.
- Those who fall behind tend to raise stakes to “just get back to even”. Chasing losses like this is one of the best-known warning signs of problem gambling.
- So a cash-out goal is not a winning strategy; at most it puts a boundary around the loss. The only reliable way to avoid the loss is not to play.
Experiment with a cash-out goal
The app shows amounts in Korean won (₩) in every language. Treat them as abstract units; only the ratios matter.
Pick a cash-out goal
On the Simulator or Stats tab, set Cash-out goal to 2x, 5x or 10x the starting bankroll. When the goal is reached the simulation stops and the app reminds you what would have happened if you had kept going.
Read the goal-reached rate on the Stats tab
With a goal set, Stats shows a goal-reached rate next to the bankruptcy rate. Try 2x, 5x and 10x and check that they stay under 50%, 20% and 10%.
FAQ
What if I also set a stop-loss?
A stop-loss caps how much you can lose; it does not change the expected value. Any combination of profit target and loss limit still averages out negative.
I keep going back to win back what I lost.
If it feels hard to control, talk to a helpline listed in the box above. Family members can call too.
Sources: NCPG, Help and treatment · GamCare, Talk to us
Martingale Bust - Roulette Sure-Win Simulator
Every amount is virtual. No sign-up, works offline. A free Android app for learning probability, in English and Korean.