Blackjack Card Counting: Learn the Techniques

Blackjack Card Counting: Learn the Techniques
Reading time: 9 minutes

Over the years there have been many skilled card counters who have used their own card counting system to maximise their results and come out on top in many a blackjack game.

This article explains the ins and outs of card counting in blackjack and how you can use it to your advantage to beat the house. There are, of course, various restrictions that apply to the use of this technique and we will go over those as well. However, as soon as you finish reading, you’ll understand how card counting works and the basic skills you need to get started to count cards in blackjack.

After that, you get a deck (or multiple decks) of cards and a couple of friends and start practising with them and up your blackjack game.

So let’s get stuck in and find out how to count cards in blackjack.

What Is Card Counting?

In blackjack, card counting is a method of determining whether the next hand will be advantageous to the player or the bank.

Card counting was originally created to try to reduce the casino advantage as much as possible and is based on a series of statistical calculations.

The aim and intent of the card counters are to keep a running count of the high and low-value cards that appear in the game, as is apparent from the game, and in doing so, to minimize the casino’s house edge as much as possible.

By counting the cards, players can determine the composition of the remaining cards before they are dealt and played, thus minimizing losses.

Card counting is also known as card reading in trick games such as spades and contract bridges. Additionally, some variants of poker can also benefit from card counting.

This strategy was popularised in the 1960s by the mathematician Edward O. Thorpe thanks to his famous book “Beat the Dealer”.


Methods to Count Cards

As a general rule, essential every single strategy one can use for counting cards in blackjack will consist of giving each card a score and adding them when they emerge from the deck, essentially keeping a running count of the cards as they are dealt, keeping the card values in mind.

If the sum is higher, it signifies that there is a higher probability for the player since obtaining a high card is a likelier occurrence. According to data accumulated from the practice, card counting can offer more options anywhere between 0.5 and 1% to the player, however, there is also the possibility of situations where there is a much greater advantage.

So, there are a few main card counting systems that are commonly used in the world of blackjack card counting, so let’s take a look at the main ones, and decide which one suits your preferences the best, so you can get practising!

Hi-Lo System

The basic, most well-renowned strategy for counting cards is the Hi-Lo Strategy.

Cards that possess a number between 2 and 6 will be given a value of +1, 7, 8 and 9 are worth 0 while face cards and the Ace card are both worth -1 respectively. As the cards are dealt, the player has to mentally accumulate the total value of the cards that have been dealt on the table.

As a result of this, let’s say when we have a card count between 14 and 16, it’s very likely a table with a high likelihood of winning, as quite a few high cards will emerge, and with them will come a high probability of receiving a 20, or the ideal scenario, a Blackjack.

If we wanted to make a more exact calculation, we could divide the total number of cards by the remaining decks on the table.

This is commonly known in the blackjack community as a “true count”.

How to Master Hi-Lo

To master the Hi-Lo strategy, you will need to practice regularly.

Begin by turning over each of the cards one by one reciting in your head the value of the checking account (CR). For negative counts, use the letter M (less or minus) in front of your figure, you will save time, for example for a -6 count say, M6.

For positive counts do not add anything, +5 will be “5”. When you have turned over all 52 cards, your count should be zero (0) since the number of small cards in the shoe and the number of large cards in the shoe are the same. If you don’t get to zero, restart in the same order as that which caused your error.

You will succeed if you ignore the previous chain of cards that caused you trouble.

Practice, Practice, Practice…

You’ll be ready for the casino game when you count an entire two-card stack in less than 25 seconds. With more and more practice, you should get your count time down to 15 seconds or better, no mistakes of course!

After that, with the help of a 6-deck shoe, practice dealing with hands and counting while playing basic strategy to perfection.

At this stage, you should be able to convert your running count to true count at the start of each of the rounds. Don’t forget, your running count divided by the number of decks remaining will give you the true count.

At first, you should probably estimate the remaining decks at ½ deck. With practice, you should make your estimate to ¼ of the deck.

Visually estimating the number of remaining decks to be dealt is the most labour-intensive part of your learning. You must make your estimate by looking at the cards already played and not those to be played.

For example, over time you will be able to compare and accustom your eye to differentiate 3 1/2, 3 ¾ and 4 decks from one another, etc. If you want to see some real-life examples of this method, watch a professional card counter in action.

Counting Cards KnockOut Method (KO)

When talking about the Knockout (KO Count) card counting system you can sleep easy knowing that basically, all the values of the cards are the same as the Hi-Lo system, with the exception being the value of the 7.

In this system, a seven is a low card and therefore a positive value, the difference being that in the hi-lo system, it is a natural card.

Due to it being an unbalanced strategy, this cements the KO strategy in the tier-one strategy class. If you start from zero and make your way through the whole deck of cards using this counting strategy, the final result won’t be zero.

In the up-and-down method, seven is neutral; however, this is an additional point in the Knock Out strategy and will add a further four points to the deck. If you count the cards correctly with this blackjack strategy, you end up with a positive four.

If you want to effectively employ the knockout card count system to your advantage, you must keep track of the total as the game progresses. Let’s say you start at zero, and a low card is drawn, add one to the total. Now your total is 1. If the next card is also low, you add another point; so when it comes to the time that a high card is put down, now you can subtract one from the total.

When a new hand starts, the count continues.

Keep in mind it is not renewed until a new shoe is shuffled. A count that is high in any sense indicates that the deck is loaded with high or low cards. A very positive count indicates that there are low cards left in the deck, and the opposite is true with a very negative count as well.

How to Master KO Method

To ascertain at which number the count will commence, there is a formula used called the IRC (Initial Running Count). If instead of playing with multiple decks of cards, you are playing with a single deck of cards, zero will be the number from which the count starts.

One thing to consider when using the KO system, you won’t start at zero every single time, so you will have to look at your situation and see which initial running count applies to you.

This method is similar to most other blackjack card counting strategies in the sense that you should practice the system at home with your own single (or multiple) decks of cards until it becomes second nature to you. To check, it’s important to note, that after counting the entire deck, ending up with a positive 4 means you’ve done the right thing.

You need to be able to keep track of the cards, without any physical tells or giveaways, and definitely don’t make a mathematical error while counting.

Once you’ve gotten used to this system, there are a few things you can learn to do to improve your time counting.

Try to remember which cards will cancel each other out; for example, a negative card cancels a positive one. So a deuce and a king would cancel each other out.

So once you get this combination memorised, which is 2 + k = 0, that k + k equals 2, it will become apparent that the time to count cards is reduced enormously. Set yourself a goal, and attempt to make an accurate count of an entire deck of two playing cards in 25 seconds.

The simple answer is yes, card counting isn’t illegal. In fact, Counting cards in blackjack is completely legal, however as you can imagine, it’s not viewed well by most casinos, as it’s putting the house at a disadvantage when they have an experienced, expert card counter at the table.

What’s more, the dealers and surveillance cameras of many casinos try to prevent the teams of players from carrying out their strategies, since the casino has everything to lose. Significantly increasing or decreasing the bet size as the game progresses is highly suspicious behaviour, but technically they can’t stop you from counting cards.

Of course, the casino can expel you if they catch you counting cards, as it’s heavily frowned upon in all casino institutions.

Counting cards in land-based casinos

Beyond surveillance systems, most brick-and-mortar casinos are increasingly taking more measures to protect themselves against this strategy, such as using court letters.

They are the place where as a blackjack card counter you can put these strategies into practice, but it will not help if the casino uses shuffling machines that automatically shuffle the cards after each game.

One has to remember that while card counting is not illegal, a casino is a private business and reserves the right to ban card counters or remove anyone from their premises if they believe they are card counting or minimising the house edge.

Counting cards in online casinos

Most online casinos use detailed continuous shuffling machines to thwart card counters, so it is virtually impossible to count cards and find the true count value in online blackjack.

When a round is over, the cards are returned to the deck and shuffled, regardless of the number of decks used.

While playing at online casinos has a wealth of advantages, unfortunately even the most advanced card-counting strategies won’t be enough to beat the algorithm of online casinos.

Interestingly enough, technology has come a long way, and there are now blackjack card-counting apps that are available for download.

The Origin of Counting Cards

For the origins of the art of card counting, we largely have Edward Oakley Thorp to thank, the man considered the father of card counting.

This American mathematician was one of those responsible for the rise in popularity of blackjack as one of the most popular casino games in recent decades thanks to his book Beat the Dealer (1962), the first work in history to talk about this technique.

After he first theorised the method and started employing it himself at Casinos in Los Vegas, Reno and Lake Tahoe, the rumour about his blackjack skills spread through the community of card game players and in just a few months he became a true celebrity in the world of casinos. A fame that placed him as a threat to gambling establishments, but it was too late.

Thorp had changed the rules of blackjack forever.

This famous book features some blackjack tricks, especially focusing on playing strategy and methods related to card counting, with which he demonstrated that anyone playing blackjack can have a small advantage over the dealer, effectively minimising the house edge as much as possible.

More than 50 years after its publication, Beat The Dealer remains one of the most popular books among blackjack lovers and card counters around the world.

Where to Play Blackjack?

After reading this guide, you might want to try your hand at card counting. Why not try out your newfound knowledge at the best blackjack online casino sites in New Zealand?


  • Blackjack Apprenticeship. “How to count cards”,
  • Wikipedia. “Edward O. Thorp”,

Blackjack card counting - FAQ

Where can I play Blackjack?

Lucky for you, CasinoCrawlers has a great list of Blackjack casinos.

How are cards counted in blackjack?

There are different methods to do it, but they are all based on assigning a specific value to the cards in order to keep track of the ones that appear. Mentally you can add and subtract the values of the cards that appear to anticipate what may remain to appear.

Counting cards, does it work for all types of blackjack?

In principle, yes. It works for all the blackjack options of how many physical casinos offer you. The technique can be used in all variants of blackjack, but they are not effective in online versions.

Can counting cards ensure that I will win at blackjack?

Not in any way. It is a technique that can help you better organize your decision-making, but it is not an infallible method to win, far from it. No practical trick or strategy can guarantee that you win because the fundamental element in blackjack is chance, hence the difficulty of winning.

Is it legal to count cards in online blackjack?

It is not illegal because no one can forbid the user from doing so, but it is a practice that has not gone far on the web. On each hand, the algorithm will completely refresh, so that count will not help you at all.

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Noah Adams
Noah Adams
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Noah is the senior content editor at CasinoCrawlers and a writer with many iGaming articles under his portfolio. Therefore, he is skilled at writing bonus guidelines, gambling strategies, and casino reviews. During his spare time, he enjoys playing Call of Duty and is a huge rugby fan.

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