The martingale system is a controversial betting theory often used in casino gambling. Dating back at least to the 18th century, the martingale system requires a player to double his or her bet each time a round is lost, on the theory that a win will compensate for a loss plus add profit. When working with an infinite amount of resources, the martingale system is generally sound, but often fails to hold up in practice.
The theory behind the martingale system is simple: a player starts out with a low bet, such as $1 US dollar (USD). If the bet loses, the player then bets $2 USD in the next round. Each round that loses requires the gambler to double his bet in the next round. Therefore, if a gambler loses five rounds in a row, his bet will have been (1+2+4+8+16), for a total loss of $31 USD. Following the system, if the gambler bets $32 USD in the sixth round and wins, he or she will have made back the $31 USD plus the profit of the bet. At two to one odds, a $32 USD bet would return $64 USD, for a profit of $1 USD.
Martingale betting is appealing to many based on the idea that eventually a losing streak will end. A person planning to make 12 consecutive bets generally believes he or she will win at least once, thereby returning all losses and creating a profit. Hopeful gamblers may also believe they are likely to win more than once in a set of bets, particularly in a game like roulette where a chance of winning seems high.
Unfortunately, critics say, theory fails to translate into practice based on one crucial issue: bankroll. The martingale system is based on an infinite bankroll, in which the gambler always has the money to double the bet. Most people, however, do have a limit to finances, and can quickly run through a set bankroll on the fervent belief that a win will show up eventually. With a bet doubling each time, an initial $10 USD bet can turn into a $1,240 loss over seven bets. On a ten bet losing streak, that loss becomes a whopping $10,230.
Martingale betting plays on a myth that helps casinos win a lot of money, namely that there is a regular pattern to wins and losses. It is important to remember that each round of a game like roulette is independent, in other words that the number that comes up is in no way based on what came up in the last spin. While players using martingale may feel they are “due” a winning spin, the roulette wheel doesn't operate according to any foreseeable probability. While an alternating pattern of wins and losses may be more likely, it is by no means guaranteed.