The question of how many decks do casinos use in blackjack is not as easy to answer as it might first appear. Most of the recent information on blackjack card counting methods indicates that a typical casino might be using between one and three decks when playing a game. Cards are dealt from the dealer’s table to the table where the player is, sometimes, dealt from the dealer’s table as well. A lot of the card counting methods (and indeed card counting rules) involve some degree of shuffling.
Of course, there are some ways of performing a card count that do not require shuffling. For example, in a multi-deck game such as the world poker tour, each player is dealt a certain number of cards face down. The dealer then counts the number of cards left in the pot – usually this is four, five or six – and then adds up the second set of numbers, called the doubled hand, to determine the outcome of the game. This is the most traditional way of how many decks a casino uses. However, it requires stopping every hand that is dealt so that the count can be performed.
In some casinos there is an option to use what is called “deck counting”. This is the use of what is known as “card counters” or “card tracking” devices – basically computer software programs that are able to calculate the odds of blackjack wins by using the number of decks (or numbers) that have been dealt. Obviously, this is the option that most players would find preferable since it is less time consuming and also provides additional betting opportunities.
The basic premise of the deck counting is that the casino will take away all of the high cards before those that are low on the deck are turned over. Then the dealer will deal twenty-four hands and count how many were high cards and how many were low cards – basically the difference between how many hands a casino has to deal and how many they have to keep. This is the basis of how many decks a casino uses.
It’s easy to see why this method tends to give a slightly lower win rate. Basically because the card counter has to rely on the luck of the draw when figuring out how many high cards are left. And while some people are good at this, others aren’t so lucky. So, essentially the card counter is gambling and in the end the casino has to pay out whether they “loved” it or not.
Some players however, like to play the “house” version of blackjack. When you go into a casino you can either start out with a real deck or you can get a non-real deck. If you are in a casino you generally only play the non-real deck. Now, when you first get the deck there may be a dealer and many times the dealer will tell you that you don’t have enough decks or that it’s time for you to start again (since you didn’t get enough cards). The casino staffers are not helping you. They are just trying to make money off of you by marking off non-selling cards.
That’s when you start to wonder – with all those decks – how many are there? Well, remember that you can only count the number of cards that are in the two decks that are face up – which means that you’ll have an idea of how many cards are in each deck. But if you use the third deck – one where the cards are face down – how many cards are in there? That’s where the problem arises.
Well, it turns out that if you want to calculate the number of decks, you just need to add the floor count, and then divide the number by two. Multiplying by three gives you the number of possible combinations. Divide by four because this is the number of possible bets, and divide by five because you might want to know how many possible losses you’ve encountered. And multiply by six because there are twelve different numbers – one for each of the two decks that the dealer will use to shuffle the deck.