Paroli system

How the Paroli system works

The Paroli betting system is a set of rules for sizing your bets on even-money bets like red or black. It pays 1 to 1, so a win doubles the chips you put down.

The rule is simple: raise after a win, reset after a loss. It is the opposite of Martingale, which raises after a loss.

1. Start with your base bet – one chip.
2. If you win, double the bet to two chips.
3. If you win again, double again to four chips.
4. If you win a third time in a row, take the profit and go back to one chip.
5. If you lose at any step, go back to one chip.

One run from the base bet to a reset is called a cycle. The tester uses three wins as the stop point.

Why Paroli loses small often and wins big rarely

In each cycle you only risk your base bet of new money. Any bigger bet uses chips you just won.

• Most cycles: you lose one chip early, often on the first spin.
• Some cycles: you win once or twice, then lose the bigger bet and end the cycle with a small loss on that bet.
• Rare cycles: you win three in a row and keep a much bigger profit.

So the shape is: many small losses, a few bigger wins. Martingale has the opposite shape – many small wins, a few big losses.

Three wins in a row on the European wheel happen far less often than one loss. That is why a big goal is hard to reach with Paroli.

What the tester shows for Paroli

The tester above is already set to the Paroli roulette system. The default run uses these settings:

• Bankroll: 200 chips
• Goal: win 50 chips, then stop
• Up to 300 spins per session
• Table maximum: 500 chips
• 20,000 sessions on the European wheel

Here is what happened:

• Sessions that lost the whole bankroll: 0.0%
• Sessions that reached the goal: 8.2%
• Sessions that ended ahead at all: 33.3%
• Average result per session: -13.4 chips
• Result the house edge predicts: -13.3 chips

Paroli almost never wipes out the bankroll, because each cycle risks so little. But it also rarely reaches the goal, and most sessions end behind.

The average result is almost the same as the house edge predicts. The house edge on the European wheel is 2.70% on every bet, and no bet pattern changes that.

Paroli vs Reverse Martingale

Reverse Martingale uses the same rule – double after a win, reset after a loss – but with no stop after three wins. You keep doubling until you lose or hit the table maximum.

• Paroli: locks in profit after three wins, so cycles stay small.
• Reverse Martingale: lets a streak run, so one long streak can bring a big win, and one loss wipes out the whole streak.

In the default run, Reverse Martingale reached the goal in 56.9% of sessions, compared with 8.2% for Paroli. Its average result was -16.8 chips.

Both systems still end with an average loss that matches the house edge. They differ in how the results are spread out, not in the final cost.

Try it yourself in the tester

Run the tester above and change the settings to see how the shape of the results moves.

• Raise the goal and watch how few sessions reach it.
• Lower the goal and see more sessions finish ahead.
• Raise the number of spins and watch the average result drift down.
• Switch the system to Reverse Martingale or Martingale and compare.

Whatever you change, the average result per session will stay close to what the house edge predicts. You can test other systems on the system tester page or read about whether you can beat roulette.

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