How Many Decks Are Used In Blackjack
We’ll take a look at how the number of decks used in a game of blackjack impacts the house edge and card counting, and the number of decks used by land-based casinos.
Technically there’s no limit to how many decks of cards can be used in a game of blackjack. While a couple of friends playing at home can play a decent game of 21 using as little as one or two decks, casino blackjack is most commonly played with six to eight decks of standard 52 playing cards, excluding jokers.
How the number of decks affect the house edge
Number of Decks Required to Play the Game Generally, if you want to involve yourself in a decent activity, you can start with only 21 cards. In most of the casinos, there are usually 6 to 8 decks used. All the 52 cards are included, and joker cards are excluded. See full list on blackjack.com.au. Blackjack comes in several variants. The game can be played with 1, 2, 4, 6, and 8 dec. But step into any casino, you will find at least five to eight decks of cards used in Blackjack game! Excluding jokers, each of these decks come with a standard 52 cards. One, with full deck penetration. That is, the dealer doesn’t shuffle until there are only a few cards left. If a casino uses six decks, and shuffles after every few hands, they. See full list on bicyclecards.com.
When optimal blackjack strategy is employed, the theoretical house edge for a game of 21 is less than 1% depending on the rules in play, making this the most player friendly of all casino card games. However, the house edge can vary significantly depending on the number of decks of cards that are used per game and the rules that are in place, with a 0.5% house edge typically reserved for fewer deck games with player-friendly rules.
As more decks of cards are added, the house edge becomes higher and higher, growing even further with the introduction of new rules that have been implemented by land based casinos to give the house an extra advantage (for example, excluding doubling on soft hands, offering lower payouts for natural blackjacks, unfair Soft 17 rules, etc).
The reason for the variation in house edge is that the more decks of cards that are used, the lower your chances are of drawing a natural blackjack (a hand with a 10 value card plus an ace), with fewer decks giving you a better chance. With fewer decks in use, the dealer also has a lower chance of drawing a natural blackjack against the player’s natural blackjack, which means there is a lower chance that a pushed tie bet will occur.
Impact on card counting
Card counting is big in blackjack, with many players benefitting in big ways from being able to mentally calculate which cards have already been dealt versus which cards remain in the shoe in order to determine their next move.
With single deck blackjack, card counting could be mastered with some work even if you weren’t the most mathematically advanced type, with many card sharks publishing bestselling books teaching their card counting methods. However, the addition of each and every deck of cards makes card counting that little bit more difficult, so counting is very difficult for casual players who might not have the time or the patience to master the technique.
Why some land based casinos use fewer decks
It wasn’t too long ago that casinos around Australia used the single deck blackjack format, with similar rules to those we’re used to seeing employed with online six deck blackjack games, which is what put the house edge around the 1% mark. As more players honed their blackjack strategy and card counting began to grow in popularity and effectiveness, the casinos had to put certain provisions in place to protect the house against these player-friendly rules.
Initially, casinos kept the single deck format but introduced some rules that were so unfavourable to players that recreational punters were turned off the game entirely, which is what led to the introduction of the higher deck games, which you’ll find at some casinos. At Australian casinos like Crown Melbourne, Crown Perth and Star Sydney, blackjack games commonly use between four and eight decks.
However, to keep players happy by continuing to offer blackjack games using fewer decks of cards, some casino vendors imposed less player-friendly rules, like restricting splits, imposing lower betting limits and paying less for blackjack wins. So while players can benefit from using fewer decks, the unfair rules make the game work in the houses favour.
These blackjack games using fewer decks and limiting rules have become favoured by Australian casino vendors as they are highly favourable to the house, much to the disdain of punters. Dedicated blackjack players should consider switching to play online where the probabilities and house edges are more favourable to the player.
Benefit of online play
Online gambling was made illegal in Australia as of September 2017 following the introduction of the Interactive Gambling Amendment Bill 2016, so for Australians the content on this page is informational in nature only. The information about online blackjack is intended exclusively for international readers.
Online blackjack games from leading developers like Microgaming and NetEnt are typically played with six to eight decks of cards, but with rules that are much more favourable to players than some of the sketchy rules being employed by land based casinos. Playing online gives players the chance to choose from several 21 variants, including Single Deck Blackjack, so you can hand pick games with better house edges using the player friendly rules that you prefer.
You’ve heard it time and time again – the fewer decks used in a game of blackjack, the better your odds.
Have you ever stopped to wonder why this is?
Single Deck Blackjack
I got the inspiration to write this blog post after fielding a question from a buddy of mine who isn’t much of a gambler. He’s preparing to head to a bachelor party in Vegas and started to study blackjack. He noticed that everyone says “fewer decks is better,” but didn’t understand. After all, he said, the overall proportion of each rank of card is the same no matter how many decks are shuffled together.
This post is all about deck size and blackjack. We’ll cover why fewer decks is better, in detail, and include a little bit of math where appropriate.
Fewer Decks = More Blackjacks
How Many Decks Are Used In Blackjack
The main reason we say that fewer decks is better for players is that, in each deck, exactly 1/13th of all cards are Aces.
Yes, my friend was right, the initial proportions of card values to one another is equal no matter how many decks you play with. The reason you’ll be dealt more blackjacks with a smaller shoe is that the impact of removing a card from the game is greater in a game with fewer overall cards.
Odds of Drawing Blackjack in a Single-Deck Game
Let’s start by getting an idea of how often a player will draw blackjack in a single-deck game. To get to the probability of drawing a blackjack from a one-deck shoe, all you have to do is multiply the odds of drawing an Ace by the odds of drawing any card with a value of ten points. We know that a single deck of fifty-two cards contains four Aces and sixteen cards worth ten points – four tens, four Jacks, four Queens, and four Kings.
That means probability of drawing any Ace is 4/52, which we simplify to 1/13. Once you’ve drawn your Ace, the probability of then drawing any ten-point card is 16/51. Notice anything about those two numbers? The first probability is based on a fifty-two card deck, but since you’ve already drawn a card, you have to now work out the probability of drawing one of sixteen ten-point cards from a deck of fifty-one.
This change in the divisor is the reason why a smaller number of decks is advantageous to the blackjack player, and gives the house a distinct disadvantage.
If you want to get an accurate number of the likelihood of drawing a blackjack from a single-deck shoe, you actually need to double your result, since you could technically get a blackjack with either a ten-point card OR an Ace at the start.
All told, the probability of drawing a blackjack from a single deck shoe is 4.83%. That’s the probability of drawing an Ace (1/13) multiplied by the probability of drawing any ten-point card (16/51), multiplied by two.
Odds of Drawing Blackjack in a Two-Deck Game
Double Deck Blackjack Strategy
To give you an idea of the statistical difference between one and two decks, let’s look at the odds of drawing a blackjack when you start with 104 cards instead of 52.
The probability of drawing any Ace from a two-deck shoe is 8/104. The probability of then drawing any ten-point card from the same shoe is 32/103. When we multiply those two together, then double the result, we get 4.78%.
Odds of drawing a blackjack in a one-deck shoe = 4.83%. Odds of drawing a blackjack in a two-deck shoe = 4.78%. By adding a deck (and not changing any rules of the game), the casino has decreased your likelihood of drawing a blackjack by 0.05%. Remember, though, that each one of those lost blackjacks would have been a win under standard casino rules at a 3:2 payout. Losing those 3:2 payouts makes a big impact on your bottom line, and on the casino’s.
Why do Double Downs Work Better with Fewer Decks?
If you’re following along closely, you’ve probably already figured out that the same phenomenon that makes blackjacks more likely with fewer decks probably also affects the likelihood of a successful Double Down. If you double your initial hand (6 and 5), you’ll be more likely to draw a face card to form a total of 21 if the game uses fewer decks.
Here’s where things get tricky – don’t forget that your dealer also benefits from these changes at lower deck counts. It’s not just the player that has a shot at more blackjacks. The reason why this fact doesn’t impact the game as much as it might is that players win 3:2 for blackjack, while the house wins just even money. Also, the dealer can’t Double Down, while the player can. That additional doubled-win gives the player a bigger advantage than the dealer.
Conclusion
All things being equal, meaning all rules being pretty much identical, a blackjack game that uses a smaller number of decks to build the shoe is advantageous for the player. One situation I’d warn blackjack players about – casinos that offer single-deck blackjack with a 6:5 or even 1:1 payout for player blackjack. The implication is that the casino is only willing to give you those improved single-deck odds in exchange for a reduced penalty at the point of player blackjack. In the case of games that don’t pay the traditional 3:2, don’t play them just because of the appeal of the single deck setup.