Counting Cards

When players enter their favorite brick and mortar casino or login to an online card room, they know full well that the odds in most games are not particularly in their favor. Games like craps, baccarat, and roulette boast a substantial house edge; but offer larger payouts to help sway gamers back to the tables. It may come as no surprise, then, that games with smaller, simpler pay rates – such as blackjack – tend to have better odds for gamers. Indeed, a player using basic strategies perfectly at a blackjack table will reduce the house advantage to roughly .5%, meaning they would win nearly half of all hands played.

While winning 49.5% of the time is an advantage players shouldn’t balk at, serious gamblers know that sending one’s win rate over the 50% mark is the best way to ensure that they stay in the black. To this end, a group of academics and card players pooled their resources to develop a mathematically derived formula to tilt player advantage at the blackjack table over the 50% mark – a strategy known as counting cards.


What is it?

Counting cards is a complex blackjack strategy that allows skilled and attentive players to more accurately predict the next card to be dealt. The strategy works by utilizing an advanced point system that takes into account the the number of decks in use at the table, number of players in a given hand, table positioning and recent deal history

Though ostensibly invented in the ‘60s, the practice was first brought to the public’s attention thanks to the exploits of a group of students from the Massachusetts Institute of Technology. Beginning in 1979, the MIT Blackjack Team began touring the casinos of the world, utilizing their card counting techniques – as well as some advanced signalling tricks and collusion – to win untold millions of dollars from gaming centers throughout the world. The inspiration for thousands of books and at least 2 films, the MIT Blackjack team helped pioneer the world of card counting – and gave the practice a black eye.

Indeed, while the team’s combination of genuine mathematical theory with signalling and cheating tactics may have earned them millions of dollars over the years, casinos eventually caught on. Members of the team are now blacklisted at casinos throughout the world, and though the practice of counting cards itself is still perfectly legal, colluding with other players in order to make it work is not. Despite it’s legality, however, card counting is typically looked down upon in modern casinos, prompting many brick and mortar operations to change around their games to help minimize player advantage.

How Does it Work?

Counting cards is an ornate process that requires players to pay close attention to every aspect of their game and apply a mathematical formula to it. A player looking to count cards will have to spend a great deal of time at the blackjack table before he or she can use the strategy to it’s full advantage. These players will sit at a given blackjack table, knowing full well how many decks are in play (information that should be evident at the table) and play through several hands using normal blackjack strategies. As they play, however, card counters make a mental note of all the hands being dealt, paying particular attention to the number of high and low cards that are drawn. Considering there are 4 cards of each value per deck, and multiplying that by the number of decks in play, card counters can gain a better understanding of what cards remain in the shoe.


There are four Jacks in every deck, multiplied by the number of decks in use.

Though this forms the base of most card counting strategies, there is a lot more involved in the process. In the most common form of card counting, the player will assign a positive, negative or neutral value to each card that comes out, depending on it’s numeric value. Cards of lower value (2-6) are rated as positive numbers, middling cards (7-9) are neutral, and 10-value cards (as well as aces) are given a negative number. These values are referred to as the effect of removal and correlate to the impact said card has on the house advantage. Lower cards, for example aid the house’s advantage, as they suggest that the higher value cards remain in the shoe to be drawn later. The exact values of these cards can vary depending on the level of computations a player is willing to make, but for the sake of simplicity, most simply rate them as 1 (low), 0 (middle) and -1 (high).

Once all cards are dealt and it is the counter’s turn to act, they must quickly calculate the sum of all cards dealt to that point. Though far from exact, this level of computation gives players a better understanding of the probabilities that accompany any further cards that may be drawn, something that, when combined with more typical blackjack strategies, can help tip the odds in a player’s favor.