Blackjack Odds

Blackjack, played perfectly, offers gamblers the best odds of any game in the casino. Because blackjack is played with any number of decks from one up to eight, the odds for a particular game may be way different from a game one table over. There are other important variables too, including the size of the crowd at the table, the specific rules for the game, and the number of deals between shuffles.

Let's take a look at a specific type of blackjack, the basic Vegas Strip game.

Vegas Strip Blackjack Odds

The most common game in Vegas pays 3:2 for blackjack, allows players to double down on any two cards, and has the dealer standing on a soft 17. Here are the player advantages for every deck size you can find on the Strip, if you play with basic blackjack strategy:

Single deck +0.02%
2 decks -0.31%
3 decks -0.43%
4 decks -0.48%
5 decks -0.52%
6 decks -0.54%
7 decks -0.55%
8 decks -0.57%

The only version of Vegas Strip blackjack where you can expect a return with only basic strategy is a single deck game, and that advantage isn't anything to write home about. A single deck Vegas Strip blackjack game is basically a break-even deal, with player advantages shrinking a few decimal points with every deck added to the hand.

But these numbers aren't written in stone. They are averages, taken from a man much smarter than me who has spent his life studying blackjack math. What can effect these numbers?

Blackjack Rules and Odds

The rules of the blackjack game you play have a big effect on your expected outcome.

The so called "benchmark" game of blackjack follows these rules:

1. Dealer stands on soft 17.
2. You may double down on any 2 original cards.
3. You may not double down after splitting a pair.
4. You are allowed to split any pair.
5. You can resplit any pair except a pair of aces.
6. Split aces get only one card each.
7. No surrender at any point.
8. Dealer gets a hole card, or the player’s original bet is lost if the player doubles down or splits a pair and the dealer wins a blackjack.
9. Insurance is allowed up to one-half of the player’s bet, paying 2 to 1.
10. Player blackjacks are paid 3 to 2.

Each of these rules alters blackjack odds to some degree, but these have been figured into the above odds. How do small changes to the rules affect blackjack odds?

If an 'early surrender' rule is in play, you automatically have an added 0.62% advantage. Late surrenders are less advantageous, adding only about 0.02% to your chances. Changes to the rules can decrease your advantage as well. At blackjack games where blackjack pays 1:1 instead of 3:2, you lose nearly 2.5% of your advantage right off the bat. A 1:1 blackjack payout may not be exactly common, but as Vegas offers more and more 6:5 blackjack payouts, blackjack players who do not count cards find themselves 1.75% less likely to win money at the tables.

Card Counting and Blackjack Rules

You know that basic blackjack strategy says you should never take insurance--the odds back up this rule of thumb. But how does card counting affect insurance strategy?

Most blackjack rules will lead to different strategy for card counters than for basic strategy types. If a blackjack game doesn't allow you to take insurance, as is sometimes the case in Reno, card counters are at a disadvantage. Counters know when it is more likely for a dealer's ace to be matched with a ten, so the inability to take insurance is a knock on their game, while it doesn't really affect people who play with basic blackjack strategy.

We can see this difference when it comes to the "surrender" rule as well. Adding the "surrender" rule to a game of blackjack increases a player's odds less than one-tenth of a percent, but a card counter gets a major boost to their game from the inclusion of the surrender rule.

Atlantic City Blackjack Odds

The standard blackjack game in Atlantic City uses eight decks, allows doubling after splits, and no resplits. Otherwise, the game is pretty much the same as in Vegas. Using a little math, it becomes clear that the eight deck game in Atlantic City is slightly more advantageous for the player against the casino--0.47% instead of 0.57% in Vegas Strip blackjack. How did we figure that?

Player advantage in any eight deck game is -0.57%. Adding the "double after splits" rule increases your odds by 0.14%, but taking away resplits reduces your odds by 0.04%. That gives you a negative expectation of 0.47%.

If you're looking for a blackjack game that offers you the best odds, look for a game with few decks, a smaller crowd, and rules that are more advantageous to the player than to the house. Follow the deck penetration (number of deals per shuffle) and learn to count cards. Once you've got all that down, you'll be playing the casino game that offers the best odds. Card counters playing at ideal tables will walk away with money pretty much every time they play.