Card counting is a strategy used in blackjack to determine when the player has a statistical advantage over the house. This is done by tracking the ratio of high cards to low cards left in the deck. The greater the percentage of tens, face cards and aces in the deck, the greater the advantage for the player. The basic idea is to bet more money when the player has an advantage and less money when they are at a disadvantage.

There are many card counting systems, but it is first necessary to learn the basics of the plus/minus point count system. This system is relatively easy and with a minimal amount of practice you will be ready to play for real. The more complex systems are variations of the plus/minus and can be easily adapted after learning the basics. There are also easier systems, such as the Ace Five count, but they are less accurate and require you to raise your wagers at a much greater rate. The way a casino can tell when you are counting cards is that you greatly increase your bets when the count is in your favor. The plus/minus system allows you to raise your bets at a more gradual and harder to detect rate.

In blackjack the player gains an advantage when the deck has a shortage of cards valued 2,3,4,5 and 6. The player is at a disadvantage when the deck has a shortage of tens, face cards and aces. By counting cards you will know when you have this advantage and be able to capitalize on it by increasing your bets. When the deck has a disproportionately low amount of face cards and Aces, you can alter your strategy by hitting on hands you normally wouldn’t. This will increase the overall number of hands that you win.

In the plus/minus point count a plus value is given to low cards, and a minus value is given to high cards. The higher the point count, the better the odds for the player. When the cards are being dealt simply keep a count in your head as you see each card. Start at zero and add one for each 2, 3, 4, 5 or 6 dealt. Subtract one from your count for each 10, J, Q, K or Ace dealt. This will give you what is known as a running count. 7, 8, and 9 have a value of zero. This is because they have a very small statistical effect compared to the other cards. There are some variations, such as the Canfield Master, that use a value of -2 for the Ace instead of -1 or give a value of +1 to the seven instead of zero. A running count is the actual count and assumes you are playing with a single deck.

This system is balanced. There are 20 cards in a deck that are valued plus 1, and 20 cards that are valued minus 1. The remaining 12 cards (7, 8 and 9) have a value of zero. At the end of a deck the count will be zero. To practice this system, take a deck of cards and flip them one by one while keeping track of the count. At the end of the deck the count should be zero. Keep practicing by flipping the cards faster and faster and do this with distractions around. You should be able to count a full deck while having a conversation and watching TV.

Once you are confident that you can quickly and accurately count cards, it is time to look at your betting strategies. The higher the plus count, the more that you want to bet. If the running count is plus 1 or negative, bet one unit. The unit can be whatever you want it to be, but is generally the table minimum for beginners. When the running count is plus 2 or 3, bet 2 units, plus 4 or 5 bet 3 units, plus 6 or 7 bet 4 units and plus 8 or more bet 5 units.

It is rare that you will play in a single deck blackjack game. The next step is to calculate the “True Count.” The true count is calculated by dividing the running count by the total number of decks that have not yet been dealt. The most common, and easiest, way to determine how many decks are left is to look at the remaining cards in the shoe and make an estimate. A more accurate, and more complicated, way is to count the number of decks played based on the number of rounds played. If there are 6 players and each average 3 cards per hand, each round will use 1/3 of a deck. Most casinos use 6 decks. So, after the first round divide your running count by 6 to figure out your true count. After the second, third and fourth rounds divide by 5. The deeper into the shoe you get, the more accurate the running count is.

When the shoe is first shuffled the dealer holds about a 0.5% advantage. Each additional true count point increases the player’s advantage by 0.5%. So, when the true count is +1, you have even odds. When the true count is at +2 the players have a 0.5% advantage.