Counting cards is a skill which is used by gamblers of card games to realize an advantage by tracking cards which have been dealt. This provides the player a theory of the sum of cards, that have to be dealt with. Counting cards is a technique that has more use in vingt-et-un than in other card game.

In blackjack, a player has an advantage when the remaining shoe has "big value cards." High cards can be faces or aces. The card counter in the casino brings into play such situations by making bigger bets, as and when they occur. A lot of accomplished gamblers use the composition of the deck to alter their overall course of action. Fairly new players occasionally experience difficulty while performing quick counting and may be subject to errors, when it comes to handling dealt cards. 21 card counting is a business by itself. Millions are made or squandered, by both the players and the gambling dens, based on card counting techniques in use.

Computing has made its presence known on counting cards too, with refined computing power impacting the complete process. Long-standing gamblers however vow that a more complex card counting plan is more prone to breakdown, negating the additional accuracy allowed by the application of technology. Anyone can dig up a lot of tactics for 21 card counting by visiting online pages dedicated to blackjack. With the game growing in fame in gambling halls around the world, there are newer strategies being developed every other day. One can dig up at least a multitude of internet sites providing you tips on counting cards and the overall strategy to earn money playing blackjack.