Blackjack is a popular card game in casinos and online casinos. It’s an easy game to play and has a low house edge. But many players wonder about how many decks are used in the game. The answer depends on a number of factors, including the rules of the game, how many players are playing, and the casino’s house edge.

#### How many decks in blackjack are there?

There are two primary types of blackjack: single-deck and multi-deck. In the former, cards are dealt from a shoe. In the latter, the dealer shuffles the cards after each hand. Both have their own advantages and disadvantages, and a player should consider them when choosing the right variation to play.

#### The number of decks in a blackjack game affects the odds.

In a game that uses one deck, the probability of getting a natural blackjack (a hand with a value card and an ace) is 2*pr(ace)+3*pr(10), which is about 1 in 21. The probability of getting a natural blackjack decreases as more decks are added to the game.

The house edge of a game with fewer decks is slightly higher than that of a game using more decks. However, the difference is very small. In fact, it’s only a few percentage points.

#### Adding more decks to a blackjack game increases the house edge.

A game that uses four decks has a house edge of 1.2%, while a six-deck version has a 3.7% house edge. Likewise, the house edge of a game that uses eight decks is 0.57%.

Counting cards in blackjack isn’t illegal, but casinos do have a negative attitude towards it. They’ll reshuffle the deck more often to avoid card counters, who can track which cards are in the shoe and make better decisions about their betting strategies.

This is why casinos tend to shuffle the deck after every hand, so that it doesn’t get too long before the cards are gone. This means that players who are counting will have a harder time keeping track of what’s in the shoe and will have to play with a smaller advantage.

If a player is allowed to double, the advantage they’ll receive is also affected by the number of decks in a game. For example, in a single-deck version of the game, doubling is estimated to increase the player’s advantage by 1.65%. This advantage drops to 1.38% in an eight-deck version of the game, though.

Another aspect of the number of decks in a blackjack game that affects the odds is the EOR, or expected odds ratio. This is the difference between the expected win and the expected loss for a natural blackjack.

The standard EOR in a single-deck game is 5.91%, while the EOR in a multi-deck game is 6.9%. The increase in the EOR per unit increase in the number of decks is most pronounced when comparing a single-deck version to a two-deck game.

If you’re looking for the best blackjack games, try to find ones that use a single deck. This will help you maximize your player advantage, and give you the highest chance of winning.