Blackjack Rule Variations and House Edge

Posted By: Date: 04/07/2012 at 12:00 am Leave a comment

Being the most popular card game in the world, Blackjack has inherited a lot of rule variations from many different sources around the world. Each of these rules will have an effect on the house edge, either positive or negative for the player.

Rules that commonly fluctuate included the number of decks used, when and how a player can split and/or double down, and the application or negation of the Soft 17 rule. Other rules that frequently vary may be the surrender rule, late surrender, blackjack payouts, double exposure of the dealer’s cards, and the 5/6/7-Card Charlie rule.

Below we will define each of these variables and describe how it affects the house edge in a casino blackjack game. We will start by identifying the effect of the number of decks used on the house edge. For your convenience, all other rules have been split into two categories; rules that benefit the player, and rules that benefit the casino.

Note that the percentages are based upon variations of the most typical rules, in which 8 decks are used, players can double on any two cards before or after a split, splits are allowed up to four times, there is no Soft 17 rule in play and blackjack pays the standard 3-to-2.

Number of Decks Used
The general rule here is to find a blackjack game that uses the least amount of card decks. The less cards in the mix, the lower the casino house edge. All of the totals below benefit the player in some way, but as you will see, the single deck rule gives the highest advantage to the player.

1 Deck: +0.48%
2 Decks: +0.19%
4 Decks : +0.06%
6 Decks : +0.02%

Blackjack Rules that Benefit the Player

These are the best rules to look for in a blackjack game as they reduce the house edge by the corresponding percentage.

  • Blackjack Pays 2-to-1: +2.27% [Very rare; natural blackjack pays 2-to-1 instead of standard 3-to-2]
  • 5-Card Charlie: +1.46% [A hand of 5 or more cards that does not exceed 21; hand instantly wins]
  • Suited Blackjack Pays 2-to-1: +0.57% [A natural blackjack with two same suited cards pays 2-to-1]
  • Early Surrender: +0.39% [Player may forfeit and surrender half of bet before dealer checks for Blackjack when dealer shows Ace]
  • Double on 2+ Cards: +0.23% [Player may double on any number of cards]
  • Hit after Split Aces: +0.19% [Player is able to draw cards after splitting aces]
  • 6-Card Charlie: +0.16% [A hand of 6 or more cards that does not exceed 21; hand instantly wins]
  • Re-Split Aces: +0.08% [Player may split aces, and re-split them if another pair of aces is dealt]
  • Double on Split Aces: +0.08% [Player may double after splitting aces]
  • 7-Card Charlie: 0.01% [A hand of 7 or more cards that does not exceed 21; hand instantly wins]

Blackjack Rules that Benefit the Casino

These rules result in a higher house edge, as shown by the negative percentages below. It is best to avoid as many of these rules as possible. There is no blackjack game that doesn’t invoke at least some of these rules. The idea is to find as few of them, preferably those with the lowest effect on house edge, paired with the least number of decks used.

  • Split 3x: -0.01% [Player’s hand limited to three Splits]
  • Double on 9-11: -0.09% [Player may only double on totals of 9, 10 or 11]
  • Split 2x: -0.10% [Player’s hand limited to two Splits]
  • No Hole Card: -0.11% [European rule in which dealer does not receive second card or check for blackjack until all players are done]
  • No Double on Split: -0.14% [Player cannot double after splitting]
  • Double on 10-11: -0.18% [Player may only double on totals of 10 or 11]
  • No Splitting Aces: -0.18% [Player may not split aces]
  • Soft 17: -0.22% [Dealer must hit Soft 17; a hand totaling 17 that includes an Ace valued at 11]
  • Blackjack Pays 7-to-5: -0.45% [Blackjack pays 7-to-5, less than the standard 3-to-2]
  • Blackjack Pays 6-to-5: -1.39% [Blackjack pays 6-to-5, less than the standard 3-to-2]
  • Blackjacks Pays 1-to-1: -2.27% [Blackjack pays even money, less than the standard 3-to-2]
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