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Testing 666 Roulette System

Last updated: 01.15.2023 by Andrew Shepard

Did you know that roulette has often been referred to as the game of the devil? This isn’t because a lot of players have a devil of a time making money at it. Instead, it’s because the sum of all numbers on the roulette wheel adds up to 666. This brings us to the 666 system which is characterized by many as a high-risk strategy. Let’s take a look at how it works and find out exactly how risky the 666 system is.

How the 666 System Works

It's a simple, non-progressive system. The 666 system involves placing multiple bets at the same time. Here’s how it’s done:

  • Wager 36 units on Red
  • Stake 4 units on each of the following splits: 0+2, 8+11, 10+13, 17+20, 26+29, and 28+31. Notice that all of these split roulette bets only cover black numbers.
  • Stake 2 units each on any three uncovered black numbers.
66 System Works

As you can see, the 666 system covers 33 of the 37 cells on a European roulette board which gives us an 89.19% chance of winning. This calls for a total stake of 66 units and it gives us four possible outcomes for each round:

  • One of the splits wins. There is a 32.43% chance of this happening and it gives us a total profit of 6 units.
  • One of the straight-up bets wins. There is an 8.11% chance of this occurring and it yields a 6-unit profit.
  • Red wins. This will happen 48.65% of the time and leave us with a 6-unit profit.
  • None of the bets win. The probability of this happening is 10.81% and it will cost us 66 units.

As it turns out, it takes 11 wins to compensate for a single loss. Let’s illustrate using five fictitious spins.

  • Spin 1

    The ball ends up in the 10 slot which means we win one of our splits for a 6-unit gain.

  • Spin 2

    The ball lands on 35 giving us a win on one of our straight-up bets. Add another 6 units to our chip stack. We are now up 12 units.

  • Spin 3

    The ball settles in the 19 slot giving us a win on our Red bet. This adds another 6 units to our win total putting us up 18 units on the session.

  • Spin 4

    This spin lands on 4 which misses everything. This sets us back 66 units on the turn and 48 units for the session.

  • Spin 5

    The last spin lands on 31 giving us a win on one of our splits for a 6-unit gain. We are now down a total of 42 units for the 5-round session.

Testing the 666 System

It is now time to put the 666 system to the test with the purpose of finding out how this betting system fares over the long run. According to the math, we can expect to win 892 of our 1,000 rounds. That adds up to a total gain of 5,352 units for the wins and a loss of 7,128 units for the 108 expected losses. As you can see, this puts us 1,776 units in the hole over the course of the 1,000 rounds. This demonstrates that the 666 system is not a recipe for long-term success.

We will now test the system in a random simulation that is based on the percentages. In this experiment, we can get a good idea of how a player’s bankroll will change over the course of 1,000 rounds. We will actually use four fictitious players who each have a starting bankroll of $1,000. The graph below illustrates the results.

Testing the 666 System

A sharp bankroll decline is experienced by three of the four players. In fact, Players 1, 2, and 3 busted out after approximately 400 moves. Player 4 got lucky early growing his bankroll to $1,570 after about 400 rounds. However, Player 4 then fell victim to the laws of averages and zeroed out his bankroll by the 800th spin.

It’s clear that the 666 system is unsustainable as a long-term approach. However, our simulation shows that it can be effective in the short term although we wouldn’t recommend using it for more than 20 moves. It’s clear that there are better betting strategies out there.

Pitfalls of Using the 666 System

With an 89.19% chance of winning, it isn’t hard to see why the 666 system garners a lot of attention. The onion in the ointment is the eleven wins that are needed to make up for each loss. The mathematics simply doesn’t support the 666 system as being a viable long-term plan of attack. You might be able to recover from one loss, but two bouncing back from two consecutive losses might be asking too much unless you get extremely hot.

Of course, another drawback to the 666 system is that you need to have a big enough bankroll. After all, the system calls for 66 units in stakes each round.


We can’t really get a handle on why this system continues to create such a buzz. Maybe it’s just the name that intrigues some players.

We simulated this strategy over 1,000 rounds and saw how it ended in disaster for every one of our fictitious players. With that said, each player had short winning spells which would seem to indicate that the 666 system can possibly be effective when used sparingly. Of course, even a short-term gain involves quite a bit of luck. The problem all comes back to needing 11 wins to make up for that one unfortunate loss.

We could advise that you tinker with the 666 system. For example, you could integrate the d’Alembert method in which you increase bets by one unit when you lose and then decrease the stake after a win. But, why would you do that? There are many more interesting and effective systems and strategies out there.

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