The most popular blackjack game nowadays is played with 8 decks of cards. Though it may seem impossible to count cards here, below you can see that the chances are still high that you will improve your odds and the graphics shows you the frequencies the count will occur. As blackjack often has such a low house edge compared to other games, many casinos fill their tables with rules that swing the favour away from the player and towards the dealer. Indeed, some venues alter their blackjack offerings to the point where they become some of. The original, world-famous strategy charts for 4-deck to 8-deck blackjack by the Wizard of Odds.
Posted byFewer Decks are Better. Do You Know Why?
When it comes to the number of decks in a blackjack game, the fewer the better. Most players have heard this fact somewhere along the line, but many of them don’t know why fewer is better.
I often get this question by email, where players will note that the proportion of each rank of card is the same whether the casino uses a single deck or shuffles six decks together. Regardless of how many decks are in play, we start out with one thirteenth of the cards being Aces…
You Get More Blackjacks in Games With Fewer Decks
Despite the initial card proportions being equal, in games with fewer decks you will be dealt more blackjacks. You will also be more successful in your double downs. How can that be, when all the ranks are equally represented no matter how many decks are used? It is because removing cards has more impact in a game with fewer decks.
How Often Will You Draw a Blackjack From a Single Deck?
To get the probability of drawing a blackjack from a single deck, we multiply the chance of drawing an Ace by the chance of drawing a ten-value card. In a single deck of 52 cards there are 4 Aces and 16 ten-valued cards (4 each of Ten, Jack, Queen, and King).
p(Ace) = 4/52 = 1/13
p(Ten) = 16/51
Note that the second line reduces the number of cards in the divisor to 51, to account for the removed Ace. And that’s where the difference lies.
We also need to double the result since we could draw either (Ace,Ten) or (Ten,Ace). Our final result is:
p(Blackjack) = p(Ace) * p(Ten) * 2 = (1/13) * (16/51) * 2 = 4.83%
The probability of drawing a blackjack from a single deck is 4.83%.
Blackjack House Edge
How Often Will You Draw a Blackjack From Two Decks
Same idea with two decks, with different numbers. 104 total cards, including 8 Aces and 32 ten-value cards…
p(Blackjack) = 8/104 * 32/103 * 2 = 4.78%.
The probability of drawing a blackjack from two decks is 4.78%.
More decks means slightly fewer blackjacks. In six decks, the probability drops further yet to 4.75%.
Double Downs Work Better in Fewer Decks Too
Free Single Deck Blackjack
The same effect impacts double downs. If you double your initial hand of (6,5) for a total of 11, then you are slightly more likely to draw a face card to make 21 if the game uses fewer decks.
Astute readers may notice that the dealer gets the benefit of these changes as well. That’s right, the dealer gets more blackjacks in single deck, and the dealer draws to 21 more often just like the player. But note that a player wins 3:2 for blackjack, while the dealer gets only even money. And for hands like the double down example, the player wins twice the initial bet. So while both player and dealer get more of these good hands, the player is rewarded more handsomely for his.
But You Get Fewer Pat 20s in Fewer Decks!
Double Deck Blackjack
It’s not all good news with less decks. For the same reason, you will get fewer dealt hands of 20! Once you remove the first ten-value card, there are only 15 tens left in 51 cards in single deck, while in double deck your chances are better with 31 out of 103.
This impact of fewer pat 20s affects players and dealers equally, so it’s really a wash.
Single Deck Blackjack
The bottom line is that, all other things being equal, you should play in games with fewer decks. Just make sure they pay 3:2 on blackjack!