Blackjack Betting Systems: Martingale, Paroli, 1-3-2-6 and 1-2-3-5 Tested

The short answer

A betting system changes how much you bet from hand to hand. It cannot change whether you win a hand: every hand is played with the same cards and the same odds whatever is on the table. So every system loses the same share of what you bet as flat betting does — about half a percent with perfect basic strategy — and most of them simply make you bet more.

We tested six popular systems with our blackjack engine to show it, using exactly the same hands for each. First, how they work.

How the popular systems work

1. Martingale. Double your bet after every loss; go back to one unit after a win. One win recovers all the losses in a row plus one unit — until a long losing streak hits the table limit or your bankroll.
2. Paroli. The reverse: double after a win, up to three wins in a row, then start again. Small losses, occasional big streaks.
3. 1-3-2-6. Bet 1, 3, 2 and 6 units on four wins in a row; after a loss or after the fourth bet, start again at 1.
4. 1-2-3-5. The same idea with a gentler climb: 1, 2, 3 and 5 units while you keep winning.
5. D'Alembert. Add one unit after a loss, take one away after a win (never below one).
6. Patterns like 2-1-2. Fixed sequences of bet sizes. Whatever the pattern, the cards don't know about it.

We tested them: 20,000 sessions each

Each session is 100 hands with a bankroll of 100 units and a table limit of 50 units, played with perfect basic strategy at our American table. Every system faced the same 2,000,000 hands.

Results in units. "Ran out of money" means the bankroll could no longer cover the next bet with room for a double or split. Simulated with our engine; the small differences in "lost per unit bet" are random noise.

Three things stand out:

• The loss per unit bet is the same for every system — about half a percent, the house edge. No system moved it.
• Systems that raise bets after losses make you bet much more (three to five times as much), so you lose more in total, even though you finish ahead in a few more sessions.
• They trade many small wins for rare big losses. Martingale finishes ahead about half the time, but one session in sixteen ends with the bankroll gone.

Why the Martingale feels like it works

Most of the time a Martingale session ends a few units up, which feels like a winning system. The catch is the streak you don't see coming: lose six or seven hands in a row — it happens a few times in every few hundred hands — and the next bet is 64 or 128 units, over the table limit or your bankroll. That one loss wipes out dozens of small wins. On average the system loses exactly what the house edge says, on a much larger total bet.

What actually changes your results

1. Basic strategy. Playing every hand correctly brings the house edge down from 2–4% for a typical player to about 0.5%. See the strategy guide.
2. Good table rules. Only play 3:2 blackjack; a 6:5 table costs about 1.4% more than every betting system together could ever save.
3. Card counting. The only way to bet more when you have the edge, because the count tells you when the remaining cards favour you. That is a betting change the cards do care about.
4. Flat bets and limits. A fixed bet of 1–2% of your session money, with a loss limit, keeps a bad streak from ending your night.