Roulette & Betting-System Simulator
Pick a wheel, a bet and a betting system. Then run a thousand sessions in a second and see what really happens to the money — not what the system promised.
Simulation settings
Bankroll paths — first 25 sessions
Dashed gold line = starting bankroll. Sharp cliffs are what a doubling system looks like when a losing streak arrives.
Distribution of session results
Spin once
Each spin is independent. The wheel has no memory.
The math in one table
| Bet | Pays | P(win) EU | Edge EU / US |
|---|---|---|---|
| Single number | 35:1 | 2.70% | 2.70% / 5.26% |
| Split | 17:1 | 5.41% | 2.70% / 5.26% |
| Street | 11:1 | 8.11% | 2.70% / 5.26% |
| Corner | 8:1 | 10.81% | 2.70% / 5.26% |
| Six line | 5:1 | 16.22% | 2.70% / 5.26% |
| Dozen / column | 2:1 | 32.43% | 2.70% / 5.26% |
| Red / black, odd / even | 1:1 | 48.65% | 2.70% / 5.26% |
On American wheels the five-number bet (0-00-1-2-3) carries a 7.89% edge.
What this simulator proves
Betting systems change the shape of your results, never their average. Martingale turns a steady small loss into many small wins and a rare, catastrophic loss. Paroli does the reverse. Over enough spins every system converges on the same thing: total amount wagered × house edge.
Run Martingale with a $500 bankroll and look at the “sessions ending ahead” number: it is high. Then look at the average result: it is negative. That gap is the whole trick. Read the full breakdown in The Martingale System: Why Doubling Up Fails and Betting Systems Tested.