Blackjack (also known as twenty-one or sometimes pontoon) is one of the most popular casino card games in the world. The name blackjack comes from the fact that when blackjack was first introduced in the U.S. it wasn't very popular, so casinos and gambling houses tried offering different bonus payoffs. One of those was a 10-to-1 payoff for a hand consisting of the ace of spades and a black jack (that is, the jack of spades or the jack of clubs). With the current rules, a blackjack hand doesn't even need to contain a jack.

1. Statistics Blackjack 21
2. Blackjack Statistics Table
3. Blackjack Statistics Dealer
4. Probability Of Getting A Blackjack

Rules

A blackjack game has a dealer and one or more players. Each player plays against the dealer. All players are initially dealt two cards and the dealer is dealt one card face down and one face up (these are called the hole card and up card respectively). Each player can then hit (ask for an additional card) until her total exceeds 21 (this is called busting) or she decides to stand (stop taking cards for the rest of the hand). Face cards count as 10 and an ace may be counted as 1 or 11. After all of the players have finished, the dealer reveals the hole card and plays the hand with a fixed strategy: hit on 16 or less and stand on 17 or more.

The player loses if she busts and wins if she does not bust and the dealer does (observe that if both the player and the dealer bust, the player loses). Otherwise, the player wins if her total is closer to 21 than the dealer's. If the player wins, she gets twice her bet; if she loses, she loses her money. If the dealer and player tie it is called a 'push;' the player keeps her bet but does not earn any additional money. If the player's first two cards total 21, this is a blackjack and she wins 1.5 times her bet (unless the dealer also has a blackjack, in which case a tie results), so she gets back 2.5 times her bet.

Soft Hand. A hand that contains an ace that can be counted as 11 is called a soft hand, since one cannotbust by taking a card. With soft hands, the basic strategy is to always hit 17 or less and even hit 18 if the dealer's up card is 9 or 10 (where the 10 refers to a 10, J, Q, or K).

Doubling down. After the player is dealt her initial two cards she has the option of doubling her bet and asking for one additional card (which is dealt face down). The player may not hit beyond this single required card. With the basic strategy, you should always double with a total of 11, double with 10 unless the dealer's up card is 10 or A, and double with 9 only against a dealer's 2 to 6. (Some casinos only allow doubling down on 11).

Splitting pairs. At the beginning of a hand, if the player has two cards with the same number (that is, a pair) she has the option of splitting the pair and playing two hands. In principle, a pair of aces should of course be split, but in this case blackjack rules allow you to get only one card on each hand, and getting a 10 does not make a blackjack. With the basic strategy, you should never split 10's, 5's or 4's, always split 8's, and, in the other cases, split against an up card of 2 to 7, but not otherwise.

Strategies for the Player

1. Blackjack Probability and Blackjack Odds. To fully understand the game of blackjack, you must.
2. Blackjack Data Repository. Blackjack Data Repository is a collection of Blackjack statistics and probabilities culled from simulations and arranged in tables. 37,856 pages of Blackjack tables are viewable including about 15,500,000 Blackjack statistics from 320,000,000,000 rounds of play.
3. Blackjack is a slightly deceptive game. Its simple rules of play may fool you into believing it is easy to master but if you delve deeper, you will quickly find this is a purely mathematical game that is all about odds and probabilities.Blackjack Hall of Fame inductees Edward Thorp and Julian Braun were among the first people to come to this realization in the 1960s.
4. The naive assumption is that the chance of each player getting blackjack is independent of the others. As you say, the chance than one player does not get blackjack is 2524 2652 The chance that none of n players gets blackjack is then (2524 2652) n.

Statistics Blackjack 21

Blackjack is almost always disadvantageous for the player, meaning that no strategy yields a positive expected payoff for the player. In the long run, whatever you do, you will on average lose money. Exceptions exist: some casinos offer special rules that allow a player using the right strategy to have a positive expected payoff; such casinos are counting on the players making mistakes.

The so called basic strategy is based on the player's point total and the dealer's visible card. It consists of a table that describes what you should do in any situation in the game (you can find an example of this table at Wikipedia). Under the most favorable set of rules, the house advantage against a player using the basic strategy can be as low as 0.16%.

Many people assume that the best strategy for the player is to mimic the dealer. A second conservative strategy is called never bust: hit 11 or less, stand on 12 or more. Each of these strategies leads to a player disadvantage of about 6%.

With the general rules of blackjack the way to win is to beat the dealer’s hand without going over 21. If you go over 21 this is called a “bust” and its an automatic loss. On the other hand, if your first two card total 21 then is called a “blackjack” and pays you 3 to 2 times your.

Edward Thorp, in his 1962 book Beat the Dealer, describes a simple strategy that makes blackjack an almost even game: if the dealer's up card is 2 to 6, play never bust; if it is 7 to ace, mimic the dealer. The exception to this simple rule is that one should hit a 12 if the dealer's up card is 2 or 3. More advanced strategies include features such as taking into account the player's hand composition (as opposed to just considering the point total) and the other players' hands, specially card counting (that consists of keeping track of the cards that have been dealt so as to know the composition of the remaining cards in the deck), and shuffle tracking (which is far more complicated than card counting, and consists in roughly following groups of cards as they are shuffled). These two last strategies are usually forbidden in casinos.

What does it mean to have a 0.16% disadvantage?

When discussing casino games, one usually finds statements such as the ones above saying something like: 'the house advantage in this game is about 0.16%'. A first explanation is the following: betting ten dollars each hand, you will in the long run lose an average of 1.6 cents per hand. It would be nice to have an idea of the probability of winning any particular bet when playing some specific strategy. Indeed, we can infer this from the player's disadvantage. Let's take, as an example, the potential 0.16% disadvantage when playing the basic strategy.

Suppose you bet $1 at each of 10,000 bets playing the basic strategy. Let's call p the total probability of winning a pass line bet (so p is the number we are trying to calculate). If p was, for example, 0.5, it would mean that, on average, half the times you should win the bet, so you would win 0.5 · 10,0000 = 5,000 times. Since each time you win a bet you get twice what you bet and each time you lose the bet you lose all the money, you would end up with 5,000 · $2 = $10,000, that is, the same total amountyou bet (10,000 times $1). In this case, the house advantage is 0%, as is the player advantage.

The same idea applies for any p: if you bet 10,000, you should, on average, win the bet 10,000p times, so your average payoff is $20,000p. In our case, the house advantage is 0.16%, so if you play $10,000, on average you end up with $10,000 - $10,000 · 0.0016 = $10,000 - $16 = $9,984. So we only have to solve the equation $20,000p = $9,984 to get p = 0.4992.

Links

You can find more information on blackjack's rules, strategies, and history on the Internet. For instance, you can try Wikipedia.

A very interesting free on-line blackjack trainer can be found here.

1. If you are dealt a point total of 16, what is the probability of busting if you hit, assuming that a whole deck will be used to choose among when you are dealt your next card?
2. If you are dealt a 3 and an ace, what is the probability of not busting if you hit, assuming that a whole deck will be used to choose among when you are dealt your next card?
3. Suppose you are the only player against the dealer, and you are in the first hand of a game played with one deck. You are dealt an 8 and a 6, while the dealer is showing a queen. What is the probability that you bust if you decide to hit?

Solutions

Return to Lesson Index

Top of Page

Blackjack Statistics Table

Blackjack odds are percentage figures which represent your probability of losing or winning a hand. They can also represent the house edge or their profit margins as well. Usually probability odds don't mean much on the short term, but they clearly average out in the long term and this is why the casinos always win over the long term.

We decided to make a few tables and charts of the most common blackjack probability odds for various scenarios and situations found while playing blackjack. The most important odds percentage represents the dealer's edge in the game. This is the long term advantage that they have which will eventually take your money away. Blackjack is actually one of the most popular games in the casino and also has some of the lowest odds of all the casino games, except casino craps of course. Generally their edge ranges from 1% to 15% depending on what variation of blackjack you are playing.

How to Beat the Casino House Odds

There is one feature that makes blackjack more desirable than any other casino game. There is actually a way to beat the house edge by increasing your odds. In fact, your probability odds in blackjack can be increase to the point where you would actually be making the profit in the long term, essentially turning the casino into a personal ATM. This practice is known as card counting and casinos don't like this because they know they will be losing money.

Before you start card counting, you should learn 'blackjack basic strategy', which is the mathematically correct way to play every move in blackjack to get the best odds. This can lower the house edge to less than 1 percent. When that percentage goes to a negative number such as -1%, then it is you who has the edge over the casino. This is when you complement basic strategy with card counting to get the highest efficiencies.

Blackjack Statistics Dealer

Odds vs. Dealer Up Card

Probability Of Getting A Blackjack

The first odds chart shows what kind of advantage the player has vs. the dealer based on what his up card is showing. The first column in the chart is what card the dealer has showing after the cards have been dealt. The second column of the table shows the dealer's probability of going bust based on each card. The last column shows the advantage the player has and the probability of winning based on the basic strategy theory. As you can see, the dealer has about a 43% chance of going bust when he has a 5 showing as an up card. At the same time, the player has about 23% advantage as well. Notice that the player advantage goes negative when the 10 cards and ace start showing up. This means the player is more likely to lose.

Dealer's Up Card	Dealer Odds of Busting	Player Advantage Percentage
2	35.30%	9.8%
3	37.56%	13.4%
4	40.28%	18.0%
5	42.89%	23.2%
6	42.08%	23.9%
7	25.99%	14.3%
8	23.86%	5.4%
9	23.34%	-4.3%
10	21.43%	-16.9%
J	21.43%	-16.9%
Q	21.43%	-16.9%
K	21.43%	-16.9%
A	11.65%	-16.0%

Blackjack odds of Busting While Taking a Hit

This chart shows the probabilities of going bust after taking a hit. Busting means that your card total would go over 21 points and would be a hard total as well. The highest score you can get when being initially dealt two cards is 21 points so you can never go bust. This means if you took a hit on a hard 21, you would have a 100% probablity of going bust, which is common sense. Also, if you have 11 points or less, it is impossible to go over 21 points on the next hit and your odds of going bust would be 0 percent.

Total Hand Value	Probability of Going Bust
21	100%
20	92%
19	85%
18	77%
17	69%
16	62%
15	58%
14	56%
13	39%
12	31%
11 or less	0%

House Advantage with Multiple Number of Decks

The number of 52 card decks in a game of blackjack influences the house edge. In some cases, the odds increase in favor of the casino when more decks are used. The advantage edge can be as much as 1% towards the casino and this is a big number in terms of odds over the long term. As you can see here, a single deck of card gives the lowest edge for the casino and gives the player better odds. Multiple decks such as eight decks increases the house edge almost 18 times more than it would for the single deck!

Number of Decks	House Odds Advantage
Single Deck	0.04%
Double Deck	0.42%
Four Decks	0.61%
Six Decks	0.67%
Eight Decks	0.70%

Two Card Frequency Odds

The next odds table deals with the first two cards being dealt or the 2 card frequency odds. Every player is dealt two cards at the beginning of a round of blackjack so this chart tells you the percentage of getting different categories of hands. A natural blackjack is only 4.8%, which essentially is an ace dealt with a ten card straight off the initial deal. Normally the odds are 3 to 2 and you would win $3 for every $2 wagered. It's a small percentage but it's the most desirable hand to get. The lowest hand you can get is two points (two aces). This is part of the decision hands group where players are usually dealt soft hands and can make decisions without going bust. This group is the most common.

The other category is the hard standing hands. These hands are somewhat desirable because of the high scores likely to beat the dealer. These are the second most frequent two card blackjack hands. Finally there is a no bust two card hand. No bust means any two card hand that won't bust on the next hit, such as any soft hand or hard hand that is 11 points or less.

Two Card Combination	Frequency Percentage
Natural 21 Blackjack	4.8%
Hard Standing (17 - 20)	30.0%
Decision Hands (2-16)	38.7%
No Bust	26.5%
Total (all two card hands)	100%

Probability Edge for Each Card Removed from Deck

The next table shows how much your odds improve after when certain cards have been dealt and removed from the deck. Certain cards taken out of the deck and increase or decrease your blackjack odds percentage and the house edge.

This is very important for card counting. If you want the absolute perfect odds in card counting, you have to acount for each small change in the odds whenever a card is dealt. As you can see from the table, when small cards are taken out of play, the odds increase in your favor overall. This is a paramount property of card counting. The opposite happens when large cards are dealt. Your odds begin to decrease. When you are counting cards, you will notice your count decreasing when large cards are dealt.

You can imagine how complicated it would be to be adding these numbers in your head while card counting at the same time. If your mind was a computer, it would be easier to keep track of the percentage. Some people can do this, and this is the way to become a perfect card counter! It is easier to keep track of the odds when playing with a single blackjack deck. For example, when five cards are seen on the table, they offer a 0.67% increase in your advantage. In fact, when a lot of fives are used up, your odds will be much higher than if any of the other low cards were used up, even the six point cards. Also, these effects are cumulative so you always need to keep track of the odds after every card is dealt. This data is actually quite amazing!

Removed Card	Effect on Odds
2	0.40%
3	0.43%
4	0.52%
5	0.67%
6	0.45%
7	0.30%
8	0.01%
9	-0.15%
10	-0.51%
Jack	-0.51%
Queen	-0.51%
King	-0.51%
Ace	-0.59%

Dealer Final Hand Probability Odds

This next table shows the odds of what the dealer's final hand will be. Usually in blackjack, the dealer must hit on 16 and stand on 17. These rules are slightly different for other variations of twenty-one. So generally, the odds of the dealer's final score being 16 are 0% because he must hit. This table will show the probability of the dealer busting or getting a non-bust hand as well as natural blackjacks.

Dealer Final Hand	Probability of Getting Final Hand
Natural Blackjack	4.82%
21 (more than 2 cards)	7.36%
20	17.58%
19	13.48%
18	13.81%
17	14.58%
Non-Bust (less than 21)	71.63%
Bust (more than 21)	28.37%