Card Counting Systems

Written by Dean McHugh
Dean McHugh
Dean McHugh is a full-time writer with more than 20 years of experience in the iGaming industry. Specialising in casino reviews, slot analyses, and sportsbook evaluations, he delivers clear, engaging, and insightful content for both industry professionals and casual players. Over the past four years, he has contributed extensively to leading iGaming comparison websites.
, | Updated: Fri 29 August 2025

One of the most important things players need if they want to win at blackjack is an effective strategy. It is essential to understand its main principles in order to apply it correctly and make it work in their favour. One of the most widely used strategies is card counting, along with the basic strategy. As the two methods are related to some extent, players should take advantage of the knowledge they provide to achieve the desired win.

The optimal strategy outlines the basic rules of the game and the best possible moves in any given situation according to the total value of the player’s hand and the dealer’s up-card, and therefore it is essential for players to know it inside out.

Importance of Card Counting Systems

The main principle of card counting is to determine whether the upcoming cards are likely to be beneficial from the player’s perspective. In order to make an accurate prediction, blackjack fans need to use a reliable card counting system. Additionally, this will enable them to keep track of the cards successfully and maintain better organisation and discipline at the table.

Card counting systems are specifically designed to help players grasp the patterns of the game and use this knowledge to improve their play. They give players the valuable opportunity to gain an advantage over the casino and increase their chances of winning. Another purpose of a card counting system is to help players keep track of the cards that have already been dealt. The so-called effect of removal indicates that every card’s removal influences the house edge to some extent.

Benefits of Card Counting Systems

Card counting systems provide players with the opportunity to alter the basic strategy accordingly and thus make better decisions regarding their bets and moves. This is why it is really important to have solid knowledge of them in order to become a proficient card counter. Thanks to card counting systems, players are able to decrease their losses significantly by adjusting their wagers in the most appropriate way.

Players who rely on card counting systems can decide whether to increase or decrease their bets, based on information from the cards on the table, and therefore prevent themselves from losing money. This is arguably the greatest benefit they gain from card counting systems, which is why the strategy is used predominantly by serious players who know what it takes to win.

How Card Counting Systems Work

A reliable card counting system does not guarantee a 100% chance of winning and players should not expect success on every single hand. Its purpose is to give them valuable information that will allow them to make better choices and thus significantly decrease their chances of losing. It teaches them how to take advantage of the shoe by determining whether it is rich or poor in power cards. Moreover, by using their knowledge of the basic strategy, they will be able to improve their game greatly and finally reach their goals.

Variations

As card counting is one of the most widely used strategies by proficient players worldwide, it has been greatly developed over the years. Nowadays, there are many variations, which give players the opportunity to choose the one that suits them best. Regardless of their different rules and patterns, the main idea always remains the same – to help players take advantage of the information the cards on the table provide.

However, they should be very careful when deciding whether a particular variation is worth trying, as each one takes a lot of time to learn; if it is not efficient enough, it will cost them money and all their efforts will be in vain. Moreover, some of the available strategies are very hard to understand and it is almost impossible to recall them in a noisy and crowded casino.

How to Choose the Best Card Counting System

Many card counting systems use the principle of assigning values to the cards, as it has proven to be very effective. The Hi-Lo system is relatively simple compared to the rest of the card counting variations. However, players need to bear in mind that complicated and advanced strategies might be more accurate but harder to recall in a casino setting. Failing to do so will prevent them from making the best choices and will most likely result in losing the hand.

When it comes to gambling, many players believe that the simpler a strategy is, the better the chance they have of applying it when needed. The phrase level of count is often used to indicate the difficulty of a particular variation of the card counting strategy. It also shows the ratio between the assigned values of the high and low cards.

Generally speaking, blackjack card counting systems can be either balanced or unbalanced. To select the right counting system based on your skill level, you have to know the differences between them. When it comes to balanced card counting systems, the sum of all card values is zero. With unbalanced systems, the sum of all card values is different from zero.

For example, the Hi-Lo system is balanced and cards from 2 through 6 are assigned the value of +1, while 10s, picture cards and aces have a value of -1. Blackjack fans who use this system add the value of all cards that have already been played. The sum is called the running count. The downside of balanced systems is that the running count has to be converted into the so-called true count, which is based on the number of decks remaining in the shoe. This further complicates the calculations, which is why many blackjack players prefer to use an unbalanced strategy. It does not require players to convert a running count into a true count. We have to admit, however, that an unbalanced system can still be somewhat complex, although it automatically takes into account the number of decks in the shoe.

To explain how it works, we would like to give an example. A popular unbalanced card counting system is the Red 7. Players who use it assign a value of +1 to cards from 2 to 6, as well as red 7s. Black 7s, 8 and 9 have a value of 0, while 10s and aces are counted as -1. When using an unbalanced card counting system, you start counting from a number different from zero. Players who opt for the Red 7 counting system use -2 as a starting count in single-deck games, -4 in double-deck games, -8 in four-deck games, etc.

Hi-Lo System

One of the best-known card counting strategies is the so-called Hi-Lo system (High-Low system). It is considered a very reliable method – easy to comprehend and use in a casino setting – which places it among the most popular. It is effective because it assigns a value to each card which can be positive, negative or zero.

This way card counting becomes easier and quicker and players are able to follow the cards successfully. When they start keeping track of the cards, they should adjust each value according to the system. The strategy sets the following values: cards from two through six are +1; seven through nine are 0; and the rest of the cards in the deck are -1.

Hi-Lo Card Counting System
Card ValueCount
2, 3, 4, 5, 6count +1
7, 8, 9count 0
10, J, Q, K, Acount -1

Red Seven

Red Seven is another level-one system, which means that it is simpler and easy to grasp. This method contains the basic card counting principles and players can be sure that they will understand how it works. Its simplicity allows them to remember it easily when needed, while at the same time providing them with a reliable and accurate plan. Thanks to it, they have the chance to turn the tables in their favour.

The system uses the familiar counting method of assigning a specific value to the cards. The number seven, as the name of the system hints, plays a significant role. The reason is that, when players have a red seven, it is counted as +1, whereas a black seven is counted as 0. The plan for the rest of the cards is exactly the same as that used in the Hi-Lo system.

Red Seven Card Counting System
Card ValueCount
2, 3, 4, 5, 6count +1
7 redcount +1
7 blackcount 0
10, J, Q, K, Acount -1

KISS

KISS (Keep It Short and Simple) is a card counting method that has three variations – KISS I, KISS II and KISS III. The updated versions are better than KISS I as they give players a greater advantage over the casino. This strategy does not involve difficult mathematical equations and is quite easy to understand.

In comparison with the rest of the methods, it is simplified, which makes it suitable for inexperienced players. This is because they do not have to count half of the cards in the deck, as the system ignores them. Counting and keeping track of the cards on the table is therefore much easier, and the chances that players will make a mistake are significantly reduced.

KISS (III) Card Counting System
Card ValueCount
3, 4, 5, 6, 7count +1
2 blackcount +1
2 redcount 0
8, 9count 0
10, J, Q, K, Acount -1

K-O

K-O (Knock Out) is a card counting strategy that resembles the Hi-Lo system and is also a level-one strategy. It uses the method of assigning a particular point value to the cards in the deck, which helps players keep track of them more efficiently and easily. According to this system, the cards are counted the same way as in the Hi-Lo system. The only card that is assigned a different value is the number seven, as this time it gets +1 instead of 0.

This is a strategy that can be easily learned. Therefore, beginners can take advantage of the benefits it offers, provided that they manage to apply it correctly. It is really important that they understand the rationale behind this system, as this will help them remember the assigned counting value and use it when needed.

K-O Card Counting System
Card ValueCount
2, 3, 4, 5, 6, 7count +1
8, 9count 0
10, J, Q, K, Acount -1

Omega II

Omega II is a level-two card counting system, as it is more complicated than the above-mentioned ones. Even though its patterns take more time to be fully understood and memorised, in the end your efforts will pay off. This system has proven to be very accurate and with it blackjack fans can significantly increase their chances of winning.

It provides them with valuable information, giving them the chance to make wiser decisions regarding the amounts they bet. Whenever players have the opportunity to gain an advantage over the casino and increase their profit, they should not let it slip through their fingers. There are also many subtleties and useful tips they can learn in order to improve their game and strategy and achieve the long-coveted victory.

Omega II Card Counting System
Card ValueCount
4, 5, 6count +2
2, 3, 7count +1
8, Acount 0
9count -1
10, J, Q, Kcount -2

Hi-Opt I & Hi-Opt II

Hi-Opt (Highly Optimum) is a card counting system with two variations – Hi-Opt I and Hi-Opt II. Both systems use the same principles. As one can guess, Hi-Opt II is the updated version and, as such, it has new point values and is classed as level two. Hi-Opt I is level one and is less complicated than the other strategies in this class.

The updated Hi-Opt systems are quite complex and thus inappropriate for beginners. To comprehend them, players need to be experienced and have knowledge of the rest of the systems and strategies. Of course, if they succeed in understanding the Hi-Opt systems and applying them correctly during the game, players’ chances of winning are incredibly high.

Hi-Opt I Card Counting System
Card ValueCount
3, 4, 5, 6count +1
2, 7, 8, 9, Acount 0
10, J, Q, Kcount -1
Hi-Opt II Card Counting System
Card ValueCount
4, 5count +2
2, 3, 6, 7count +1
8, 9, Acount 0
10, J, Q, Kcount -2

Zen Count

Zen Count is another level-two card counting system, developed to help players gain an advantage over the casino by using more simplified assigned point values. However, it is still moderately complicated and therefore it is not the best option for beginners. The Zen system has some subtleties and for this reason it is best for players to take their time to practise it.

If they are not able to recall the system in the blink of an eye at home, then they should refrain from going to the casino. The famous method of trial and error is to be avoided when it comes to gambling, as it can lead to significant losses. The only way players have the chance to win and make a profit is if they know the card counting system like the back of their hand.

Zen Count Card Counting System
Card ValueCount
4, 5, 6count +2
2, 3, 7count +1
8, 9count 0
Acount -1
10, J, Q, Kcount -2

Halves

Halves (Wong Halves) is a very complicated card counting system whose level of count is three. It is suitable for experienced players who have dealt with other card counting systems before and have solid knowledge and understanding of their main principles. If applied correctly, it gives them an accurate count of the cards in the deck, which enables them to make wiser decisions about their bets and moves.

If this method is combined with the basic strategy, it can result in some mouth-watering winnings. The reason why this system is considered more complicated is that some of the assigned values of the cards are fractions, which makes the counting more difficult. If players want to take advantage of this system, they need to be ready to dedicate a lot of time and effort to it.

Wong Halves Card Counting System
Card ValueCount
5count +1.5
3, 4, 6count +1
2, 7count +0.5
8count 0
9count -0.5
10, J, Q, K, Acount -1

Conclusion

Over the years, many card counting systems have been developed and improved in order to provide better chances for players to win at blackjack. Some of them are hard to understand, while others are simpler. Regardless of their type and patterns, they all aim at one thing – to provide players with a reliable method that will help them make better decisions and gain an advantage over the casino. Whichever variation players choose to follow, they need to be familiar with the basic strategy if they want to become proficient card counters, as the two strategies are correlated and the card counting system cannot work properly without it.