Blackjack Odds

Even though Blackjack is a so-called “even money” game, paying 1-to-1 on most wagers, the odds of winning are definitely not 50:50. Because the dealer’s hand is always played last, the house enjoys a slight advantage, also known as the “edge,” “vigorish,” “vig,” or “juice.” No matter how slight this margin may seem, it is the source of the table’s profits and the reason most Blackjack players lose over the long term, unless they do something to put the odds more in their favor, such as advantage play or card counting.

Understanding the House Edge

To demonstrate how the house edge works, consider the novice who plays by the House Rules for the dealer when making decisions about his/her hand. Such a player would never double or split and never take insurance or surrender. No matter what card the dealer shows, this player would hit until reaching seventeen or higher, just like the dealer must do.

At first glance, an observer might think that the dealer and player would win an equal number of times over the long term. After all, they play their cards the same way. In fact, it might appear that the player has the edge, getting paid 3-to-2 for every natural blackjack, while the dealer only gets 1-to-1 for such a hand.

But consider what happens when the two both go bust by exceeding twenty-one. In every instance, the dealer wins, because the player is out of the action before the hand ends. This makes a huge difference in the odds. Playing by the House Rules, the dealer and player can each be expected break once every 3.57 hands, or 28% of all deals. Calculated as 0.28 x 0.28, the dealer and player should both bust on the same hand 7.84% of the time.

By contrast, a natural blackjack occurs much less frequently—just 4.8% of the time—and some of those hands will result in a push. Even when paid at 3-to-2 on the rest, the effect of the higher payout is negligible. The true house advantage reduces to 5.9%, which means the player can expect a net loss about once every 17 hands, again assuming that all hands are played exactly the way the dealer would play them.

Shifting the Advantage

Novices quickly learn that playing as the dealer doesn’t pay, whereas playing according to Basic Blackjack Strategy does. They learn when to hit and stand depending on the situation. Following the basics reduces the number of times the player busts, too, from 28% to just 17%, bringing the built-in house advantage down to.17 x .28 or 4.76%.

They also learn how take advantage of the options to take insurance or surrender. When success bonuses for doubling down and splitting pairs are factored in, the house edge falls to as little as 1%. That’s equivalent to a single net loss every 100 hands, instead of once every 17 or 21. The importance of learning and playing according to Basic Blackjack Strategy cannot be over-stressed.

The House Rules by which Blackjack is played also impact the odds. There are many versions of the game. Each table features different nuances, including the how many decks are used, whether or not the dealer stands on soft 17, when doubling down and splitting is permitted, etc. One estimate has put the number of possible rule combinations at almost 7,000, and each of them has an affect on the odds.

In a classic single-deck game, where the dealer stands on soft 17, shuffles after every hand, and allows doubling down after a split as well as on any two first cards, optimum play should actually give the player an overall advantage of 0.15%. Of course, casinos know this, so very few still offer such a game. Instead, they reduce the payout for a natural blackjack to 6-to-5, one little change that results in a house edge of 1.24%.

Much more common are tables that retain 3-to-2 blackjack payouts, but deal multiple decks from a shoe, restrict splitting, resplitting and doubling down, or do not offer a surrender option. Each of these rule variations adds to the vigorish. In fact, simply having the dealer hit on soft 17 instead of standing is worth 0.19% to the house.

Changing up playing strategy can help swing the odds back in the player’s favor, but choosing a table that offers advantageous rules is of paramount importance. Knowing which Blackjack games to avoid is equally important. The lower the house’s inherent margin, the more likely the player will be to win.