How to Count Cards in Blackjack?

how to count cards blackjack

Card counting in Blackjack is one of the most widely discussed topics on the Internet, where threads about it are popping up everywhere. However, this subject remains one of the most misunderstood in the world of casinos and some “well-informed” people are in a hurry to present their counting theories, without any relevant source or very detailed reflection.

Perhaps because these stories speak of people who dared to do what we all would like to do. Perhaps because these stories are about ambitious people who have successfully refined the science of Blackjack into an effective way to make money. Maybe because we would like to win as much as possible at the casino. In this article, you will be able to discover some of the most effective techniques for counting cards in Blackjack as well as some tips to avoid being spotted.

A Little History of Card Counting

Blackjack has long presented an advantage of more than 5% in favor of the casino. Over time, this advantage has diminished or even been reversed in favor of card counting players.

For years, the casino operators have offered visitors blackjack tables, and the players did what they had to do: lose their money. Most of the losses were caused by players with no previous gaming experience. Casinos found their advantage in this slight advantage over even experienced players, who often did not take the trouble to understand the Blackjack strategies. They rather saw it as a game of chance and ignored a possible optimization or strategy. For years, casinos could, therefore, afford to ignore the mysteries of the game they offered. This is simply because only a few players were able to turn the game to their advantage.

In the 1950s, everything changed for casinos. A short article by Roger Baldwin devoted to the analysis of the best ways to play each hand from a mathematical point of view appeared in the United States. This basic Blackjack strategy indicates to the player the most profitable action mathematically, according to his cards and that of the dealer. But at that time, the advantage was still in favor of the casino, namely 1%.


During the 1960s, a math teacher, Edward Thorp, realized that the Blackjack game could be an advantage for the player if he had an idea of ​​the cards still in the shoe. Edward Thorp was the author of the first blackjack card counting method in his book ” Beat the Dealer”.

A wave of panic hit the casino owners: the control of the game was now in the hands of the players. To make counting impossible, the Blackjack rules were quickly changed in all Las Vegas casinos. The number of card decks was changed, as was the way in which cards were cut and shuffled, thus preventing easy winnings for counters. The problem was that many blackjack players, who did not count cards, particularly, did not appreciate these changes to the rules at all. They deserted the casinos, which lost a very important source of profit.

Finally, to seduce dissatisfied players, the casinos relaxed the rules of the game and the players returned to the tables. The news spread and the new “counters” then rushed by the thousands in the casinos. But the novice and inexperienced players lost their money, and the casinos ultimately pulled through. Blackjack overtook craps and became the most popular table game in casinos in the late 1970s.

Why Is Blackjack So Popular?

The great popularity of Blackjack is based on a premise which, although it is true, remains a kind of fantasy for most casino players. Because these discoveries on the possibility of beating Blackjack in the casino using a counting system, the message launched to the population is: if you are brilliant, you can beat the casinos in Blackjack. The reality is quite different and requires much more than being brilliant.

What Does It Take to Be a Professional Blackjack Player?

  • Perfect knowledge of the basic strategy of the Blackjack game being played.
  • The mastery of a recognized counting system.
  • The ability to visually estimate the number of decks remaining to be distributed and to convert the RC (running count) into TC (true count).
  • Knowledge of the game clues that modify the basic strategy depending on the count for the chosen system.
  • A wagering strategy developed for the chosen game, taking into account several factors, including the rules and conditions of play. This strategy is mathematical and does not depend on luck.
  • A bankroll calculated according to an acceptable risk of losing as well as a given rate of return, all this according to the variance associated with the target game.
  • Perfect mastery of oneself, one’s emotions, and concentration in a game situation.

The few points listed above are the result of hundreds of hours of training in counting, learning the clues of the game, reading and understanding dozens of books dealing with the subject. Once these concepts are well understood, the professional player will spend as much time developing his strategy of setting up his bankroll and the risk he is ready to accept. Everything will go through millions, or even billions of simulated hands, to obtain a fair forecast of the chosen strategy.

In a word, a very small handful of people are capable of such dedication and such passion in this game which then becomes a job.

There are many young people in casinos sitting down at the table with just enough knowledge to try their hand at this, but not enough to be long term winners. Because it is a long-term issue. A professional player can spend a whole year in casinos and traveling around the world without having a positive result twelve months later.

But the message of casinos is still the same… Come visit us and if you are brilliant, you will win. Everything surrounding card counting, legendary counters like Uston or even more recently those of the famous MIT team, make this popularity of Blackjack even greater and casinos should be grateful to these characters. Card counters are the biggest free advertising (or almost) that casinos have been able to afford. The truth is that professional card counters are a very scarce commodity.

And for the few that exist…

The counters do not take money from casinos, they bring money to the casino through those who try to look like them.

Principle of Card Counting in Blackjack

While the odds in roulette and other casino games are fixed, the odds in blackjack vary with each hand depending on the composition of the shoe: cards are drawn without replacement, each draw influences the composition of future draws.

Counting cards involves following certain cards, or all cards, with certain methods, to obtain the ratio of weak or strong cards remaining to be dealt.

If the ratio indicates that there are more high cards to play in the shoe, it is said that the shoe is “hot”. The card counter will increase its bets because statistically, the cards will be in its favor: The dealer will bust more often (exceed 21), the players will make more blackjacks and start with more significant hands.

blackjack counting cards

How It Is Done

Most card counting systems start counting at 0. This means that when the first card is dealt, the count is zero. Depending on the card counting system used, this count will fluctuate after each card distributed to which a value will be assigned: for example, +1, 0 or – 1 in the Hi Lo system. You must follow not only the cards that are dealt to you but also the cards dealt to each player and to the dealer.

When the shoe has a high percentage of high cards (we say that the shoe is “hot”), the player has several advantages:

  • The dealer will bust more often (exceeds 21)
  • Players will make more blackjacks
  • Players will receive more strong cards and will start with larger starting hands.


So, when the card count is high, the card counter bets higher sums because he has a high mathematical advantage of winning against the casino: this does not, however, assure him of winning every time.

Card counting does not stop there, even if you bet more and win more, you must stay focused and keep counting and tracking cards. If the card count falls, becomes neutral or negative, then you must bet less because the casino will have a greater advantage.

What Is the Recommended Card Counting System?

The simplest counting system is the HI-LO or plus / minus count, notably used by the MIT team.

Most card counting systems use positive counting. When the card count is positive, this means that there have been more low cards played and that the shoe now contains a higher percentage of high cards.

Can You Count Cards in Online Blackjack?

In online casinos, the deck is shuffled each time, so there is no possibility of counting cards. Only the basic strategy will allow you to reduce the house advantage. There are versions of blackjack called “live” where the dealer is filmed and distributes the cards, so it is still possible to count the cards, but the shoe being shuffled after half of it is dealt, the advantage is tiny.

In the US, in most land-based casinos, the shoe has six decks of cards. It is, therefore, possible in some casinos to count cards, it is a question of finding the right table (without automatic shuffler / CSM) with the right dealer and the right conditions (calm, double on all cards, abandonment allowed).

Is It Possible to Count Cards in the Us?

The answer is simple: yes. The real difficulty is not so much knowing how to count cards, but to benefit from the bankroll so that it becomes advantageous by limiting the risk of ruin as much as possible.

Counting Cards… With Others

The film Las Vegas 21 presents a method used by MIT students which consisted of counting cards as a team to maximize the profitability of card counting. Various teams have been assembled to improve profitability and hide this count.

count cards blackjack

Image credit: Columbia Pictures

Are There Techniques Other Than Card Counting to Gain an Additional Advantage?

Shuffle tracking is probably the result and evolution of card counting. Since the high cards (faces and aces) give a significant advantage to the player, some follow the heap of these cards in the shoe to increase their stake when they appear.

“Ace Steering” is the method used to “steal” the Ace when the method called “Ace Sequencing” is used.

These techniques are very advanced and require a great mastery of card counting.

Card Counting in Blackjack: The Hi – Lo System

Developed by Harvey Dubner in 1963, the Hi-Lo system is certainly one of the easiest to master and therefore one of the most widespread.

Besides the fact that it is relatively easy to approach, its great popularity among professionals is because it is versatile. This is a system is called “balanced”, because the sum of the values ​​assigned to high (faces) and low cards is zero. Its correlation level is 0.97 for bets and 0.51 for game variations.


The prerequisite for this system is the total mastery of the basic strategy that corresponds to the rules of the casino that you will compete against.

How the HI-Lo System Operates

What is it exactly? A value is assigned to each of the cards in the game, regardless of the types (heart, diamond, etc.). Cards 2 to 6 count for +1, value cards 10 and Aces count for -1 and cards 7-8-9 count for 0 (zero).


Cards                     Values

2, 3, 4, 5, 6             Count +1

7, 8, 9                     Count 0

10, J, Q, K, A           Count -1

At the start of each shoe, you will keep a cumulative count of each of the cards that will be dealt each turn, and until the end of the shoe. For example, if you play alone against the dealer and your first hand is 10-5 against the “3” of the dealer, your current account will be +1. If for example you choose to stay on “15” (as dictated by the basic strategy) and the dealer draws two consecutive “10” to overtake with a “23”, your count will then be -1 since the sum of the values of cards 10-5-3-10-10 is -1 (note that a “10” also counts as a face such as Jack, Queen or King).

What to Do with the Card Count

Keep counting, yes. But what to do with this information? When Edward O. Thorp revolutionized Blackjack in the 1960s, it was primarily because he had just published proof beyond any doubt that an imbalance between low and high cards greatly affected the advantage in Blackjack. Indeed, when the cards remaining in the shoe and those to come are mainly low (2 to 6) the advantage is increased for the dealer; similarly, when the majority of the remaining cards are faces (value of 10 and Ace) the advantage is increased for the player. Increased benefit, but by how much?

Running Count and True Count

To fully understand the “quality” of your advantage or disadvantage, you will need to do a little exercise. You will have to convert the running count or RC into a true count or TC. Here is a simple example. You are playing against a shoe of 6 decks. You start your count at the very start of the shoe. After a few rounds, your RC is +20. Two (2) packs have been distributed and four (4) remain to be released. What is the value of your TC? Your RC of +20 tells you that in the four remaining packs there is a surplus of 20 faces (since 20 low cards were counted in addition in the first 2 packs). The TC being the count of ONLY ONE PACK, you will have to divide 20 by 4 (4 packs remaining) for a TC of 5. So, you now know that on average, in each of the 4 remaining packs there is a surplus of 5 faces per package. You have a TC of 5. You now have valid information.

What to do with this information? This information will be used to precisely establish your advantage (or disadvantage), to vary your bets accordingly and, as needed, to deviate from the basic strategy to use a strategy reflecting the remaining composition of the shoe.

How to Train for Hi-Lo

To successfully master the Hi-Lo system, you will need to practice regularly. Here is how. Start your training with a single card pack. Start by turning over each card one by one, memorizing the value of the current count (RC). For negative counts, use the letter M (minus) before your number, you will save time, for example for a count of -6 say, M6. For positive counts do not add anything, +5 will be 5. When you have finished the 52 cards, your count should be zero (0) since the number of low cards and faces is equal. If you do not reach zero, start again in the same order as that which caused your error. This will allow you to identify the chain of cards that caused you the problem.

When you are comfortable enough with this method (one pack in less than 35-40 seconds flawlessly) practice turning the cards two by two, familiarizing yourself with the value combinations of two cards. You will be ready for the casino game when you count a whole deck of two cards at a time in less than 25 seconds. With practice, you should lower your counting time to 15 seconds or better without error of course!

Subsequently, using a shoe of 6 packs (you can get casino quality cards in all souvenir shops of casinos) practice by distributing hands and counting while playing to perfection the basic strategy. At this stage, you should be able to convert your RC to TC at the start of each round. Remember, your RC divided by the number of remaining packs will give you the TC. At the beginning, you will probably have to estimate the remaining packages at 1/2 package. With practice, you will have to estimate by 1/4 of a pack.

The visual estimation of the number of packages remaining to be distributed is a part of your learning that requires a lot of work. You must make your estimate by looking at the cards already played and not those to be played. To practice your visual estimation, make a few piles of cards of different sizes in order to exercise your eye on the estimation. It’s very important. You can, for example, compare and accustom your eye to differentiate 3 ½, 3 ¾ and 4 packages from each other, etc.

Counting Tip

In a casino situation, you do not deal with the distribution of cards during the dealer’s first round. Your count begins with the dealer’s card and continues by counting the cards two by two while the latter deals the second card of each player. Thereafter, the cards are counted one by one until the next hand.


Have fun!


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