You've probably heard of , Fibonacci, D'Alembert, Labouchere. They all claim to beat roulette. They don't.
The : double your bet after every loss. In theory, your next win recovers all previous losses plus one unit profit. In practice:
1. Table limits. A $10 starting bet with a 7-loss streak requires $1,280 on the next spin — most tables cap well below this.
2. limits. Even without table limits, a 10-loss streak requires $10,240. Real bankrolls run out.
3. The math hasn't changed. The on every spin is still 2.70%. Over 10,000 spins you're still expected to lose 2.70% of everything you wagered. Systems just shift WHEN you lose, not IF.
Run the numbers: at the /advanced/bet-spread page you can see the Monte Carlo simulation — 1,000 sessions on red, $500 , $10 base bet. About 15% bust outright. The rest average a small gain but with massive .
The only "system" that matters: play European, bet minimums, keep sessions short, quit when ahead.
Key points
✓Every spin is independent — past doesn't affect future
✓Martingale requires infinite bankroll AND no table limits
✓All systems preserve the house edge (2.70% or 5.26%)
✓Flat betting minimizes variance
✓The Monte Carlo sim proves it — try it on /advanced/bet-spread