The Fibonacci system got its name from the famous Fibonacci numbers, a set of numbers where any number is the sum of the previous two. It goes like this:
0, 1, 1, 2, 3, 5, 8, 13, 21,34
This sequence can be found all over the place in nature, and was the inspiration for a roulette system. What makes the Fibonacci system popular is that it has very little variance, compared to the Martingale, which requires people to have enormous bankrolls due to the crazy swings in winnings an losses. When you use this betting strategy, your losses will be less severe, but you will also need more time to break even when a loss occurs.
The Fibonacci system was designed for even money bets, the system doesn’t work with single money bets or any other types of bets. The sum of your bets has to equal the previous two bets if you lose.
Let’s look at an example. Choose the sum you are going to bet, and play with that until you lose. Let’s say you decide to bet 5 dollars. When you lose, you have to bet 10 dollars, which is 5 plus 5. If you lose again, you have to bet 15, which is the sum of the previous two bets, 10 plus 5. In case you would lose again, you would have to bet 15 plus 10, the sum of the previous two bets.