Blackjack Odds & Probabilities

Blackjack strategy, applied perfectly, makes blackjack one of the most potentially lucrative games in the casino. If you play blackjack by the numbers, the House only has an edge of half a percent. That means if you spend $100 at a blackjack table in an hour, and you play using perfect basic strategy, you only stand to lose about 50 cents. The low house edge makes blackjack a truly cheap form of entertainment.

Blackjack rules give the game a certain purity of probability, a statistical beauty that statisticians and math nerds have exploited over the years to come up with blackjack strategy. Odds and probabilities are a huge part of winning at blackjack, so if you want to win big money at the casino, you have to understand the game’s odds and probabilities.

Blackjack Math

Blackjack strategy cards are sold at every casino gift shop in Vegas. These cards range from simple “if ___ happens, do ___” suggestions all the way up to cards with multiple rule change options on strategy. Casinos sell these cards because most people are more interested in playing a game and making big gambles than methodically picking apart the House using blackjack math and a little plastic card.

Blackjack math gives players an informed opinion about what move to make next. Rather than taking a random gamble, blackjack strategy uses odds and probabilities to tell you the move most likely to end in you beating the House. Blackjack strategy tips are more than educated guesses, they have hard math to back them up.

Here are some blackjack math basics: any deck of 52 cards contains a certain number of cards worth 10 points and a certain number of cards worth their face value. The odds of pulling a single face value card, like a 7 or a 9, is 4 out of 52. or 7.69%.

There are 16 cards in a standard deck with a value of 10 points: four 10s, four Jacks, four Queens, and four Kings. That means the odds of drawing a 10-point card are 16 out of 52, or 30.8%.

Players are four times more likely to draw a card worth ten than any other card value. 10 point cards outnumber all others, so most blackjack strategy is built around figuring out the probability of the player or the dealer drawing those high point value cards.

Using Blackjack Odds & Probabilities

The math behind the game of blackjack has a direct effect on proper blackjack strategy. We just saw how much more likely a blackjack player is to draw a 10 point card than any other card, but how does that effect blackjack strategy? At the most basic level, knowing that you’re more likely to draw a card worth ten points makes a point total of 12 or more an anxious game decision.

Another example of how blackjack odds play a big part in player strategy is what blackjack experts call bust probability. Bust probability is a number that indicates how often a certain point total will lead to a bust. Since the blackjack dealer doesn’t have free will, and must stand at 17 in most casinos, his bust likelihood is higher when his point total is 16, because dealers have to hit at 16. This rule also affects early dealer point totals—imagine a dealer with an upcard of 6. He has to hit, and we already know how much more likely you are to draw a ten point card than any other, putting him in great danger of drawing a 16 and being forced to hit into a bust.

Other Blackjack Odds & Probabilities

Blackjack math is straightforward, since each card in the deck has its own consistent point value and there’s a clear line drawn between winner and loser. Applying a little bit of math, blackjack experts have figured out the odds of being dealt different types of blackjack hands. Your chance of drawing a natural 21, and winning instantly, is 4.8%. Play 100 hands of blackjack and you’re likely to only be dealt a natural blackjack 5 times.

That makes blackjack sound like a hard game to beat, but the truth couldn’t be more different. Those same odds show that the most common hand dealt in blackjack is the decision hand, any point total between 1 and 16. These hands are dealt 38.7% of the time, meaning that out of every 100 hands you play, you’ll have to make a decision only about 40 times. In the other 60 hands, the decision will be made for you.

If you play with basic strategy, and make the right play according to that strategy for each of those decision hands, you can minimize the house edge.

A final trick to using blackjack odds to beat the House is considering two crucial statistics at once. We’ve already talked about dealer bust probability and player edge against the House. Just combine the two statistics for an idea of when you have the best chance to beat the blackjack dealer.

For each dealer upcard, mathematicians have figured out their likelihood of drawing to a bust. For example, if a dealer’s upcard is a 2, his bust probability is 38%. Factor in the player’s advantage gained by using basic strategy against each upcard, and you get a good look at when you have your best shot at beating the House.

The House is in the most danger of busting or losing to basic strategy when the dealer’s upcard is a 5 or 6. When the dealer shows a 5 upcard, his bust probability is 42.89%. Since players have a 23.2% advantage against that upcard if they play with perfect strategy, it’s clear that when a dealer shows a 5, players are more likely to beat the dealer.

Using blackjack math and odds to your advantage against the casino is called basic blackjack strategy. Make sure and pick up a blackjack strategy chart next time you hit the casino, and work on memorizing the proper play for different game situations. Following the lead of smarter blackjack players who have gone before you is important if you like making money on the gambling floor.