When playing blackjack, the number of decks you use is important. Depending on the rules of the game being played, you may need as few as one or two decks, or as many as six.
The main reason for this is that different cards fall on different numbers of consecutive spots on a deck. This is especially important when playing with a single deck, because if all of the card are drawn from the deck at once, it can make it difficult to calculate your odds.
When playing with two decks, each deck has 52 cards. If you want to play with three decks, each deck has 54 cards. And if you want to play with four decks, each deck has 56 cards.
This means that in order to have a fair game, you need at least three decks. If you’re using four decks, it’s always a good idea to have a fifth deck available in case someone accidentally drops one of their own decks while playing.
