No betting system turns a casino game in your favour. Systems change the size of your bets, not the odds of the bets themselves, so the house edge stays exactly where it was. What does make a difference is choosing games and bets with a low edge, making the right decisions where a game has them, and managing your money so a bad run doesn't take more than you planned. This guide covers the common systems, what they really do, and the few places where your decisions matter.
Betting systems and what they do
| System | How it works | What it does to your results |
|---|---|---|
| Martingale | Double the bet after each loss | Many small wins, then a rare loss far bigger than all of them |
| Reverse Martingale (Paroli) | Double after each win, reset after a loss | Many small losses, an occasional bigger win |
| D'Alembert | Raise the bet by one unit after a loss, lower it after a win | A milder Martingale; long losing runs still grow the bet |
| Fibonacci | Follow 1, 1, 2, 3, 5, 8… after losses, step back after wins | Slower growth than doubling, same long-run cost |
| Labouchère | Bet the sum of the first and last numbers of a list; cross off on wins, add on losses | Looks like a plan; bets can grow quickly in a bad run |
All of them rest on the same mistake: the idea that past results change future ones. Each spin, roll or hand is independent, and every bet carries the same edge whatever size it is.
The Martingale, worked through
Start with €5 on red at European roulette and double after each loss:
| Losses in a row | Next bet | Lost so far |
|---|---|---|
| 3 | €40 | €35 |
| 5 | €160 | €155 |
| 7 | €640 | €635 |
| 9 | €2,560 | €2,555 |
Every winning sequence earns just €5. Seven losses in a row on red happen about once in 106 tries at European roulette, and table maximums often stop you from placing the next bet. The rare loss wipes out the many small wins, and the average result is the same 2.70% of everything staked.
The Kelly criterion
Kelly is a formula for how much of a bankroll to bet when you have an edge: the bigger the edge, the bigger the stake. With a negative edge, which every casino game has for the player, the formula says to bet nothing. It is only useful where you have a genuine edge.
Where your decisions do matter
| Game | What you control | The difference |
|---|---|---|
| Blackjack | Basic strategy | House edge 0.28%–0.43% with it, more by guessing |
| Video poker (Jacks or Better) | The paytable and optimal play | 99.54% return on a 9/6 table, 97.30% on 8/5, 95.00% on 6/5 |
| Blackjack from a shoe | Card counting | A realistic 0.5%–1.5% player edge, only where cards aren't reshuffled every hand |
| Roulette | The wheel | 2.70% on single zero, 1.35% on even money with La Partage, 5.26% on double zero |
| Baccarat | The bet | 1.06% on Banker against 14.36% on Tie |
In video poker, the numbers in the name are the payouts for a full house and a flush per coin. Check the paytable before you play: the game looks the same at 9/6 and 6/5, but the 6/5 version costs about ten times as much on average.
Managing your money
- Set a session budget you can afford to lose and split it into units; one bet of 1–2% of the budget makes it last through normal swings.
- Decide a loss limit and a time limit before you start. A "win goal" doesn't change the odds, but stopping while ahead keeps the money.
- Don't raise stakes to recover losses; that is the Martingale by another name.
- Use the casino's deposit and loss limits; our guide to playing safely shows how.
For the maths behind all this, see our guide to casino maths.
Betting systems: FAQ
Does the Martingale system work?
No. It wins small amounts often and loses a large amount rarely; the house edge on every bet stays the same, and table limits can stop it entirely.
Is there any strategy that beats the casino?
Not in standard casino games. Card counting can give a small edge in blackjack dealt from a shoe that isn't reshuffled every hand.
What is the best strategy for slots?
There is none that changes the result. Choose a high-RTP version, a stake that fits your budget, and a time limit.
What does 9/6 mean in video poker?
A full house pays 9 and a flush 6 per coin. With optimal play, 9/6 Jacks or Better returns 99.54%; 6/5 returns 95.00%.
Sources
- Wizard of Odds: house edge of casino games (blackjack, baccarat)
- Wizard of Odds: Jacks or Better paytables (99.54%, 97.30%, 95.00%)
- Wizard of Odds: card counting introduction (0.5%–1.5% realistic advantage)
- Wizard of Odds: roulette basics (single zero, double zero, La Partage)
- Martingale table and odds of a losing run: our own calculations
Checked 29 October 2026.
