Casino Gambling

Blackjack Rule Variations

Rules That Effect The House Edge

by Bill Burton

for About.com

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By using basic strategy when you play Blackjack you can reduce the house edge down to the minimum however this will vary depending on the rules of the game where you play. Each casino can have a different set of rules and these different rules can modify the house edge in favor of the casino or the player. Once you know the rules of the game at the casino where you are playing you can calculate the exact house edge that you will face when you use basic strategy. The base figure for calculating the edge starts with the number of decks used in the game.

Number of Decks
Single deck = No advantage
Double deck = + 0.35%
Six Decks = + 0.58%
Eight Decks = 0.61%

If you look at the figures above you will see that with a single deck game the casino has no advantage but it jumps to about a third of a percent for the double deck game and a little more than a half of a percent for the six deck game.

Once you know the number of decks being dealt this will become your base figure for calculating the house edge. Included in this figure are the rules that you can double on any two cards and the dealer stands on 17 whether it is hard or soft.

You can then add or subtract the amount that the rule variations to this number. The rule variations are listed in the chart below. The rules with a minus symbol are favorable to the player and you will subtract that amount from the base game. The rules with the plus sign are unfavorable rules and you add that amount to the base game. Here are the most common variations.

Favorable Rules
Double After Splitting (DAS): This allows you to double down after you split a pair. For example if you split a pair of 2’s and received a 9 on one of them for a total of 11 you could double down. Doubling after splitting cuts the house edge by 0.13 percent.

Resplitting of Aces:When you split aces you receive one card on each ace. In most casinos you are only allowed to spit aces one time. If you receive an ace on your split hand you are stuck with a 12. If the casino allows you to resplit aces it cuts the house edge by 0.08.

Late Surrender:This rule allows you to surrender your hand and give up half of our bet on your first two cards after the dealer checks for a blackjack. This cuts the house edge by 0.07 percent.

Unfavorable Rules
Dealer Hits Soft 17: In most instances the dealer will stand on a total of 17 including a soft 17 consisting of an ace and a six. In some casinos the dealer will hit a soft 17 and this increases the house edge by 0.22 percent.

Double on 10 and 11 only: Some casinos only let you double down if your first two cards total 10 or 11 instead of allowing you to double on any two cards. Restricting you to this increases the house edge by 0.25 percent.

Blackjack Pays 6 to 5:Instead of paying 3 to 2 for a natural blackjack, some casinos are paying $6 to $5. This rule increases the house edge by 1.40 percent and is one of the worst rule variations. Do Not play a game with this rule.

Examples

At casino A, you find a six deck game (+0.52) that allows you to double down after splitting (- 0.13) and you can take later surrender (-0.07). The house edge for this game is 0.32 percent.

Across the street at Casino B, they are dealing a double deck game (+ 0.32) but the dealer hits soft 17 (+0.22) and you are only allowed to double down on 10 or 11 (+0.25). The house edge for this game is 0.79 percent which makes it worse than the six deck game at casino A.

This is why you should always check the rules before you sit down to play Blackjack.