Card counting

Card counting is a strategy employed by some blackjack players to determine when they have a probability advantage over the house. Almost universally, this means that the player is tracking the ratio of high to low cards remaining in the shoe. The basic premise is that a deck rich in aces and tens is good for the player. A deck rich in small cards is good for the dealer. When the odds are in the players favour bet amounts and playing strategy may be altered from standard basic strategy.

Quick Links: | MIT blackjack team | Ace/Five count | Knockout (KO) count | Hi-Lo count | Counting & the Law | Card counting movies | Counting in ‘Live Dealer’ Games | Additional reading

The advantage that an experienced card counter has over the house is between 0.5% and 1.5%. Due to this relatively small advantage, any gains will only be noticeable over hundreds of hands of play. Even then, financially it is not likely to be as rewarding as films (like 21) make card counting out to be. It would be better to see card counting as a strategy to milk casinos for comp points, hospitality and other offers.

There are a number of different card counting strategies that the player can employ. However simple or complex the strategy all systems will assign positive, negative or neutral values to the cards that are dealt in the game. Low cards are assigned a positive value because they increase the percentage of high cards remaining in the shoe. High cards are assigned a negative value for the opposite reason.

All of the various card counting strategies can be classified as either balanced or unbalanced systems. A balanced system (such as Hi-Lo) requires that the count (the total of the values from dealt cards) is converted into a ‘true count’ by dividing by the number of decks remaining in the shoe. For example, in a single deck game where half the cards have been dealt and the running count is +2, the true count would be 2/0.5 = 4. This would be considered a very high count in a single deck game and the bet stake should be increased accordingly. Only a rough estimate is required for this conversion. In another example if the running count was +7 with approximately 4 decks left the true count would be 7/4 = 1.74. This figure is rounded to +2 to keep things simple.

Unbalanced card counting systems do not require this conversion from running count to true count. Examples of unbalanced systems include the Knockout count (K-O) and the wizard’s Ace/Five count. Because these counts do not require the additional conversion step needed in balanced systems they are considered more suitable for beginners.

Advanced strategies (those that have multiple simultaneous counts or require frequent conversions) offer a slight statistical advantage over some of the more simplistic unbalanced systems but in reality gains are small. It is better to know a ‘simple’ strategy well and to play more hands per hour than to employ a complex strategy, forcing you to play slower and therefore play fewer hands.

Important note: please be aware that card counting will generally not work online. This is because most online casinos shuffle the deck after every round making any counting strategy useless. There are however, a minority of casinos that shuffle after a set number of cards have been dealt. Please satisfy yourself of the methods employed by the particular casino before playing.

Counting systems:

• Hi-Lo count
• Knockout (K-O) count
• Wizard’s ace/five count

More about counting:

• MIT blackjack team
• Card counting movies (21 & Rain Man)
• Counting in ‘Live Dealer’ Games
• Additional reading (card counting books)