Probability Of Winning Blackjack
We first present the probabilities attached to card dealing and initial predictions. In making this calculus, circumstantial information such as fraudulent dealing is not taken into account (as in all situations corresponding to card games). All probabilities are calculated for cases using one or two decks of cards. Let us look at the probabilities for a favorable initial hand (the first two cards dealt) to be achieved. The total number of possible combinations for each of the two cards is C(52, 2) = 1326, for the 1-deck game and C(104, 2)=5356for the 2-deck game.
The odds of hitting a particular card other than a 10-value card are 7.7%, and 31% for 10-value cards. As a player you can expect to hit a Blackjack once every 21 hands on average. When the dealer is showing an Ace upcard, there is a 31% chance that the dealer has Blackjack. You can expect to win at least 48% of the hands you play. P both = P blackjack × 3 × 15 ( 50 2). By the inclusion/exclusion principle, the probability of at least one getting blackjack is the sum of probabilities of each individual getting blackjack minus the probability of both getting blackjack (removes redundant overlap): 1 − P either or both = 0.90524. The odds to get a blackjack (natural) as arrangements: 128 / 2652 =.0483 = 4.83%. The generalized formula is: Probability of a natural blackjack = (A. T) / C(R, 2) A = number of Aces remaining in the deck; T = number of 10-valued cards remaining in the deck; C. There are loads more rules variants – the above are just a few common ones. For example, if you find. Blackjack Odds and Probabilities Blackjack, unlike other gambling games is not considered a game of chance, it is one that you can win if you start applying some knowledge. Unlike many other games where the result depends on player luck only, this game provides probabilities depending on.
Probability of obtaining a natural blackjack isP= 8/663 = 1.20663% in the case of a 1-deck game andP = 16/1339 = 1.19492%in the case of a 2-deck game.
Probability of obtaining a blackjack from the first two cards isP= 32/663 = 4.82654%in the case of a 1-deck game andP = 64/1339= 4.77968%in the case of a 2-deck game.
Similarly, we can calculate the following probabilities:
Probability of obtaining 20 points from the first two cards isP = 68/663 = 10.25641% in the case of a 1-deck game andP= 140/1339 = 10.45556%in the case of a 2-deck game.
Probability of obtaining 19 points from the first two cards isP = 40/663 = 6.03318%in the case of a 1-deck game andP = 80/1339 = 5.97460%in the case of a 2-deck game.
Probability of obtaining 18 points from the first two cards isP= 43/663 = 6.48567%in the case of a 1-deck game andP= 87/1339 = 6.4973% in the case of a 2-deck game.
Probability of getting 17 points from the first two cards isP= 16/221 = 7.23981%in the case of a 1-deck game andP= 96/1339 = 7.16952%in the case of a 2-deck game.
A good initial hand (which you can stay with) could be a blackjack or a hand of 20, 19 or 18 points. The probability of obtaining such a hand is calculated by totaling the corresponding probabilities calculated above: P = 32/663 + 68/663 + 40/663 + 43/663 = 183/663, in the case of a 1-deck game and P = 64/1339 + 140/1339 + 80/1339 + 87/1339 = 371/1339, in the case of a 2-deck game.
Probability of obtaining a good initial hand isP= 183/663 = 27.60180%in the case of a 1-deck game andP= 371/1339 = 27.70724%in the case of a 2-deck game.
The probabilities of events predicted during the game are calculated on the basis of the played cards (the cards showing) from a certain moment. This requires counting certain favorable cards showing for the dealer and for the other players, as well as in your own hand. Any blackjack strategy is based on counting the cards played. Unlike a baccarat game, where a maximum of three cards are played for each player, at blackjack many cards could be played at a certain moment, especially when many players are at the table. Thus, both following and memorizing certain cards require some ability and prior training on the player’s part. Card counting techniques cannot however be applied in online blackjack.
The formula of probability for obtaining a certain favorable value is similar to that for baccarat and depends on the number of decks of cards used. If we denote by x a favorable value, by nx the number of cards showing with the value x (from your hand, the hands of the other players and the face up card in the dealer’s hand) and by nv the total number of cards showing, then the probability of the next card from the deck (the one you receive if you ask for an additional card) having the value x is:
This formula holds for the case of a 1-deck game. In the case of a 2-deck game, the probability is:
Generally speaking, if playing with m decks, the probability of obtaining a card with the value x is:
Example of application of the formula: Assume play with one deck, you are the only player at table, you hold Q, 2, 4, A (total value 17) and the face up card of the dealer is a 4. Let us calculate the probability of achieving 21 points (receiving a 4).
We havenx = 2, nv = 5, so:
.
For the probability of achieving 20 points (receiving a 3), we havenx = 0, nv = 5, so:
.
For the probability of achieving 19 points (receiving a 2), we havenx = 1, nv = 5, so:
.
Odds Of Winning Blackjack With 3 Hits
If we want to calculate the probability of achieving 19, 20 or 21 points, all we must do is total the three probabilities just calculated. We obtainP = 9/47 = 19.14893%.
Unlike in baccarat, where fewer cards are played, the number of players is constant (two), and the number of gaming situations is very limited, in blackjack, the number of possible playing configurations is in the thousands and, as a practical matter, cannot be entirely covered by tables of values.
Sources |
A big part of the gaming situations that require a decision, where the total value held is 15, 16, 17, 18, 19 or 20 points, is comprised in tables in the section titled Blackjack of the book PROBABILITY GUIDE TO GAMBLING: The Mathematics of Dice, Slots, Roulette, Baccarat, Blackjack, Poker, Lottery and Sport Bets.You will also find there other issues of probability-based blackjack strategy . See the Books section for details. |
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Blackjack Probability and Blackjack Odds
To fully understand the game of blackjack, you must understand and master blackjack odds. It's crucial to know how the casino gains its edge and how it helps them win. It's also important to understand blackjack odds such as the odds of hitting a 10 or the odds of being dealt a blackjack. You can read over these blackjack odds charts to help understand the logistics behind blackjack.
Casino and Dealer Advantage in Blackjack
In most casino games of blackjack, the house advantage (the dealer advantage) is ~ 8%. The house gets this advantage by the dealer being the last player to act. By acting last, all other players have already made their decisions and could quite possibly bust before the dealer has his turn.
By using correct blackjack basic strategy, you can turn the casino edge in blackjack from 7%-8% down to 0.5%. If you correctly use advanced card counting techniques, you can often change blackjack odds and give yourself the advantage over the casino. Manipulating the house odds to your favor is the reason most casinos don't allow card counters to play blackjack.
Probability of Busting on a Hit
It's very important to know the probability of your hand busting when you are holding any total in the game of blackjack. The following odds chart shows the blackjack odds of busting, depending on your current hand value:
Probability Of Winning In Blackjack
| Hand Value | % Bust If You Hit |
|---|---|
| 21 | 100% |
| 20 | 92% |
| 19 | 85% |
| 18 | 77% |
| 17 | 69% |
| 16 | 62% |
| 15 | 58% |
| 14 | 56% |
| 13 | 39% |
| 12 | 31% |
| 11 or Less | 0% |
Two-Card Count Frequencies
This interesting blackjack odds chart is the two card count frequency chart. This chart shows the percentage chance that you will be dealt a hand in each given value range. The most important frequencey to note is the chance of being dealt a natural blackjack (natural 21 value. The odds of being dealt a natural blackjack are merely 4.8%. Following this chart you will see that the most common two card hand, at 38.7%, is a hand totaling 1-16, which is considered a decision hand.
| Two Card Count | % Frequency |
|---|---|
| Natural 21 | 4.8% |
| Hard Standing (17-20) | 30.0 % |
| Decision Hands (1-16) | 38.7% |
| No Bust | 26.5% |
| TOTAL | 100.0% |
Dealer Final Hand Probabilities
This blackjack odds chart shows the dealer final hand probability. These are the percentages that the dealer will end up with a hand totaling each corresponding value (up to 16). Read over this chart to understand the odds that the dealer has to make his final hand.
| Dealer Final Hand Value | % | Cumulative % Total |
|---|---|---|
| Natural 21 | 4.82% | 4.83% |
| 21 (3 or More Cards) | 7.36% | 12.19% |
| 20 | 17.58% | 29.77% |
| 19 | 13.48% | 43.25% |
| 18 | 13.81% | 57.06% |
| 17 | 14.58% | 71.64% |
| 16 | 28.36% | 100.00% |
Player Advantage vs. Dealer Up Card
The first two columns in this odds chart explain the dealer's chance of busting, depending on the up card that he is showing. You should note that the dealer has the highest chance of busting when he is showing a 5. The third column in this chart shows the player advantage of using basic strategy, compared to each up card the dealer is showing. You can see that the player has the highest advantage of 23.9%, when the dealer is showing a 5. When the dealer is showing any card that is 9 value or higher, the player is in the negative advantage range.
| Dealer Up Card | Dealer Bust % | Player Advantage % with Basic Strategy |
|---|---|---|
| 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% |
| J,Q,K | 21.43% | -16.9% |
| A | 11.65% | -16.0% |
Effects of Removing Cards from a Deck
When looking at the odds of removing certain cards from a 52-card deck, some cards have a much greater effect on blackjack odds. To create the strongest card counting system ever invented, you would have to incorporate all of these slight and subtle differences into the numbers to be a completely accurate system.
Removing every 5 from a deck cards would make the largest impact of improving your blackjack odds, as a player. On the other hand, removing every Ace from a deck of cards would make the largest impact on improving the odds for the casino.
| Card | % Effect of Removal |
|---|---|
| 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% |
| A | -0.59% |
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