Learn How to Count Cards in Blackjack
From the basics of Hi-Lo to counting cards with single or multi-deck blackjack games, read through our article and discover how you can beat the house. 
Anje LombardAugust 1, 2022
In a nutshell, card counting in blackjack can be described as a way for players to get an edge over the house by applying a simple mathematical equation. How does counting cards work? Simple. The practice of card counting is based on the basic principle that in blackjack, past events influence future events. Specific values are assigned to cards, and as soon as the cards have been shuffled and dealt, these values are counted while you play blackjack online or at land-based casinos.
We’ve listed some handy card-counting basics below:
- A player assigns a value to each card based on its face and number, either negative, positive, or zero. For example, there is a +1 count for cards 2 through 6, a 0 or neutral count for cards 7 to 9, and a -1 count for cards 10 through Ace.
- Counting begins at 0. Players will add value to the count as each card is dealt. Accordingly, if an Ace, King, 2, 7, 6, 4, and 5 are dealt, the count is +2. Face-down cards are not counted until they are flipped.
- The true count is calculated to determine the profitability of bets and is calculated using the running count.
- When a player is confident of the ‘true count,’ they can alter their bets according to their advantage.
- With fewer cards left in the shoe, the player makes more decisive wagers and improves their true count.
- As cards are dealt out of the deck, the counting continues. It is based on the count that betting decisions are made. It is ideal for a player to place a higher bet if the count is positive and a lower bet if it is negative.
Running Count vs. True Count
The running count in card counting when it comes to blackjack allows players to keep track of high and low value cards where cards 2-6 are attributed a value of +1, neutral cards, or 7-9, are valued at 0, and high cards (10, J, Q, K, A) are valued at -1.
A running count with a positive number does not necessarily mean that you would have the edge over the house though. To determine whether you should increase your bets, you need to consider the true count first. In general, a true count of +2 or higher is considered an indication of the player having an edge and that profitable bets can be placed. To calculate the true count, the running count is divided by the number of decks remaining.
Your advantage increases as the true count increases. Therefore, when the house has an advantage, or when the true count is low, players should wager as little as possible and increase their wagers proportionally.
Tip: To successfully count cards in blackjack, be sure you start counting when the shoe is empty to get accurate calculations!
Blackjack Card Counting Systems
Blackjack players use various card counting systems and strategies, some of which are more distinctive than others. The level of difficulty of these varies from straightforward to advanced. The level of difficulty of the system should however not dictate which one you use, as several factors influence the applicability of the system. A straightforward system will be easier to apply in a simple game with fewer decks, for example. Each system is aimed at solving a specific problem and not every system will be ideal for every game. Next, we provide an overview of each to illustrate how to apply them.
There are three main types of systems:
| Balanced/Unbalanced System | Where Balanced systems always begin and end in 0, and Unbalanced can end in |
|---|---|
| Level 1 or Level 2, 3, 4 System | Where Level 1 values can be 1, 0, or -1, with the other levels being more complex with higher values included. |
| Ace Side Count | Counting and or keeping track of how many aces have been played. |
Hi-Lo System
- System Type: Balanced, Level 1
- Difficulty Level: Beginner
- Ace Side Count: No
Probably the most common and easiest strategy, Hi-Lo card counting is based on the basic principle of calculating the ratio of high and low cards left. More high cards would be beneficial to the player, while more low cards would be beneficial to the dealer.
Card values are allocated as discussed earlier, with low cards (2-6) valued at -1, neutral cards (7-9) valued at 0, and high cards (A, J, Q, K) valued at +1. As a result of the combination of neutral, high, and low cards in a deck equal to zero, the Hi-Lo strategy is a ‘balanced’ counting strategy where the count will always begin and end in 0.
The Hi-Lo system requires you to calculate a running total of all cards played in the game, including those held by the dealer and other players, which is known as the running count. It is however the true count that will indicate the ratio between high and low cards. This does not have to be an exact calculation but can be an estimate.
To explain the Hi-Lo counting system in classic blackjack we’ll look at an example:
Once the dealer introduces a new shoe to the table, the Hi-Lo strategy begins. Since no cards have been dealt, the running count is 0. Once the first round of cards is dealt, players can calculate the running count by adding all visible cards (face-up cards) on the table.
Let’s say there are five cards on the table, an Ace (-1), 2 (+1), 6 (+1), 9 (0), and a 7 (0). Adding these totals would give you a running count of +1. Next, to determine whether it would be a good idea to increase your bets, you need to calculate the true count by dividing +1 by the total decks left on the table.
Here’s another example of calculating the true count:
In an 8-deck blackjack game, you have a running count of +7. The shoe has roughly four decks left, giving you a true count of +1.75, or 2.
Omega II System
- System Type: Balanced, Level 2
- Difficulty Level: Intermediate
- Ace Side Count: No
Bruce Carlson developed the Omega II card counting system for intermediate-level players, although today it is considered a complex system used by experienced players only. The reason a lot of experienced players use this system is for the accuracy it offers since it is a two-level system. Aces and 8s are valued at 0, cards 2, 3, and 7 have a value of +1, 4-6 have a value of +2, 9s are counted as -1, while the 10 and the face cards are valued at -2.
Since 4-6 cards are considered the worst cards in blackjack, they are valued at +2 and of course, the 10 and face cards (J, Q, K) are valued at -2 as these cards can get a player to get a natural blackjack quicker.
The fact that this is a multi-level system might make it a little bit more complicated to calculate as you play. As with the Hi-Lo system, a true count needs to be calculated by dividing the running count by the number of decks left in the shoe.
Hi-Opt I & II Systems
- System Type: Balanced, Level 1 (Hi-Opt I), Level 2 (Hi-Opt II)
- Difficulty Level: Intermediate
- Ace Side Count: Yes
There are two Hi-Opt systems, Hi-Opt I, and Hi-Opt II. While these two systems are different, they are related and we’ll therefore discuss both here.
Card values in Hi-Opt I consist of:
- 10 & Face Cards: -1
- 3-6: +1
- Everything else: 0
Players must keep a running count while also keeping track of Aces. To make informed bets, the true count is calculated by dividing the running count by the number of decks left in the shoe.
Card values in the Hi-Opt II system:
- Aces, 8 & 9: 0
- 10 & Face cards: -2
- 2 & 3: +1
- 4 & 5: +2
- 6 & 7: +1
It is important to note that the Hi-Opt II system is notably harder to master than the simpler Hi-Opt I. Since it is a two-level system, players have two card values to add and subtract by. 2, 3, 6, or 7 receive a +1 value. As soon as the players see cards 4 and 5, they must add 2 to their running count. In the case of 10 and the face cards, players need to subtract 2 from their running count. The value of an Ace, 8 or 9, is 0. As with the Hi-Opt I system, the true count is calculated by dividing the running count by the number of decks on the table.
Wong Halves System
- System Type: Balanced, Level 3
- Difficulty Level: Advanced
- Ace Side Count: Yes
This system was developed by Stanford Wong and is also the only one that makes use of fractions. Here is a quick overview of card values in the Wong Halves system, keeping in mind that three values are to be tracked when using it:
- Aces & 10s: -1
- 3s, 4s, 6s: +1
- 8s: 0
- 9s: -0.5
- 2s & 7s: +0.5
- 5s: +1.5
To avoid fractions, players can double the value of ½.
To determine the odds of winning, convert the running count to a true count. Calculating the final count after each deck would be a good idea. It’s easier to do this than to calculate a final count from several decks of cards. If you are avoiding calculations with fractions, remember to double the number of decks you would have divided the running count by.
Red 7 System
- System Type: Unbalanced, Level 1
- Difficulty Level: Beginner
- Ace Side Count: No
As a one-level system, the Red 7 system of counting cards in blackjack is simple and easy for beginners to learn. The system works based on high and low cards and is seen as a variation of the Hi-Lo counting system. Aces and 10s are valued at -1, 2-6 cards are valued at +1, red 7s in the deck count as +1, black 7s are valued at 0, and all 8s and 9s are also counted at 0. Thanks to singling out red 7s, there is no need for players to calculate a true count.
As with other unbalanced systems, counting starts with a negative count, with every deck of cards equalling -2. When playing with six decks then, you would start counting at -12. A running count of 0 indicates that you have a 0.5% edge over the house. When the running counts increase, bet sizes are increased by increments depending on the number of decks you are playing. In a nutshell, it is better for the players if the final running count is higher when using this counting system.
KO System
- System Type: Unbalanced, Level 1
- Difficulty Level: Beginner and Intermediate
- Ace Side Count: No
Commonly known as the Knock-Out card counting system and is suitable for both beginners and intermediate players. This system was introduced in a book entitled Knock Out Blackjack written by Fuchs and Vancura.
Like the Hi-Lo method, tens, queens, jacks, kings, and aces are assigned a -1, whereas 2-7 are assigned a +1. On the other hand, 8s and 9s are marked as 0. When all cards have been dealt, the final count will not equal zero, indicating that the system is not balanced. This also means that there is no need to calculate a true count.
Unlike other systems, counting does not start at 0, but the number of decks determines the starting count. When the game is played with two decks, the count would start at -2, playing with six decks means you will start counting at -20, and eight decks will have you starting from -28. If you play with a single deck you would start counting at 0 as with the other counting systems. Bet sizes are increased as the running count climbs, with lower bet sizes placed the lower the running count.
Zen Count
- System Type: Balanced, Level 2
- Difficulty Level: Intermediate
- Ace Side Count: No
Another balanced system is the Zen Count, where the count decreases to 0 at the end of the game. It is also one of the simplest systems, and the cards are valued as follows:
- 2, 3, 7: +1
- 4, 5, 6: +2
- 8, 9: 0
- 10, Jack, Queen, King: -2
- Ace: -1
Since this is a balanced counting system, players need to calculate the true count by dividing the running count by the estimated number of decks left. The Zen Count system is considered to be one of the best counting systems to help players decide when to raise their bets. This is due to the favorable correlation the system offers, standing at 0.96. Bets are increased as the true count increases, with a true count of 0 or less requiring a minimum bet size. Of course, players must also be aware of this steady increase to avoid catching the casino’s attention.
Dynamics of Team Card Counting
Team card counting is in no way a new phenomenon, with multiple blackjack card-counting teams trying to up the house all over the globe. The most popular blackjack team is without a doubt the MIT card counting team, a team that started in the 70s and is also the inspiration behind the popular movie 21. Teams use a variety of counting systems, but notably, the system used by the MIT card counting team is largely based on the Hi-Lo system, which assigns the same values to each card. As a result, high cards are -1, low cards are +1, and the rest are 0. The team also used a three-person team strategy that included:
- A big player,
- A controller
- A spotter.
After the spotter verified that the count was favorable, they would signal the big player to place the bet. The team could beat several casinos and make millions of dollars within a short period.
How to Count Cards with 1 Deck vs. Multiple Decks
Now that we’ve covered the basics of card counting and explained some of the systems you can exploit, we’ll skim over how to apply your knowledge when playing single-deck or multi-deck blackjack games.
1 Deck Card Counting
Using the Hi-Lo system, players in single-deck games only need the running count to assess their advantage. A true count isn’t necessary. As a result, you can spend more time applying basic strategy to single deck blackjack card counting.
New card counters will enjoy single-deck blackjack games thanks to the simplicity it affords. With fewer decks, players have the best odds, and beginner counters can easily track their advantage. Additionally, single-deck blackjack has a house edge of just 0.16%.
Online casinos sometimes add restrictions to single-deck blackjack games to tip the odds in their favor. For example, some rules restrict players’ moves and winnings, such as limiting re-splits and letting the dealer hit on a soft 17.
Counting Cards with Multiple Deck Games
Learning how to count cards in blackjack with multiple decks can seem tricky, especially since players have to keep track of both the running and the true count. This can be done using a balanced counting system like Hi-Lo. Using the true count, every card counting system can be used in blackjack, regardless of the number of decks.
You can adjust your bets accordingly when you know how many high-value cards are left in the shoe. To calculate the true count, the running count is divided by the number of decks on the table, which will give you an indication of the total number of high cards left. Let’s look at a practical example:
If you are playing with six decks, and you have a running count of +12, the true count will be two (12 ÷ 6 = 2), indicating two high cards left per deck. Where this calculation might get tricky is keeping track of the number of decks left on the table—keeping in mind that the importance of an accurate true count increases as the number of decks left decreases.
How Casinos Try To Prevent Card Counting
While card counting at land-based casinos is common, and certainly not illegal, one cannot help but wonder whether or not it is possible to count cards online. Can you count cards in online blackjack? Yes, it is possible! It is, however, extremely difficult. Online casinos use the following methods to reduce or eliminate a card counter’s advantage in live blackjack:
CSMs (Continuous Shuffling Machines): It is impossible for players to count cards when the dealer is using these devices. Decks (typically between 3-5) are constantly shuffled, making it impossible to calculate the variance between high and low value cards left.
Deck Penetration: Referring to the distribution of cards dealt before reshuffling, deck penetration is a cornerstone of successful card counting. In some online casinos, 8-deck shoes are replaced after 50% of the cards have been played, rendering card counting ineffective.
Rounds Per Hour: In card counting, the general rule of thumb is that the more rounds you can play per hour, the more you can win. The speed of live blackjack games limits the number of hands played and the overall winnings of card counters.
Blackjack Rules: A 6:5 payout or the dealer hitting on soft 17 can increase the house edge so much that card counting becomes impossible. These, among other game rules, are sometimes implemented to counter-act card counting.
Card Scanning: Before adding cards to the table, dealers sometimes scan them. Then, the casino’s systems analyze players’ betting patterns and table cards to identify any counting.
Look for online casinos that pay 3:2 for live blackjack, if you want to play live blackjack. Choose a table where the dealer manually shuffles the cards or uses a batch shuffler. You can still count cards with these systems depending on deck penetration. Lastly, look for live blackjack games with favorable rules.
Tips for Mastering Card Counting in Blackjack
Some players struggle to keep track of their cards when they combine card counting systems with basic strategy. Before even attempting card counting, players should know basic blackjack strategy by heart. Once you’ve got the basic strategy down, you’ll need to practice card counting until it becomes second nature. Below are some exercises you can try.
- Read the basic blackjack strategy chart out loud several times a day to ensure you can recite it without looking at it.
- Practice your knowledge of basic strategy by playing at home until you are comfortable with your level of knowledge and understanding.
- Next, you need to practice your card counting and reaching accurate running counts. Start by counting the values of a single deck of cards, until you’ve reached the last card. If you did not reach a running count of 0 you made a mistake. Continue practicing and counting for as long as is necessary.
- Once you are confident that you can automatically calculate and keep track of the running count, it’s time to put what you’ve learned to the test. Ask a friend to play with you, and play a couple of rounds to test your skills.
- Next, it’s time to see how your running count skills fare in practice. Visit a casino and watch other blackjack players play. Try to keep track of the running count as you watch. It’s essential not to attempt playing at this stage yet, you still have to practice calculating the true count!
- To practice calculating the true count, get your blackjack gear out and get ready to do some maths. You’ll need six decks of cards and 30 pieces of paper with the numbers 1-30 written on it. With an empty discard tray, pull a number from the ones you’ve prepared and divide it by six (six decks on the table). Continue pulling numbers and doing the division by six. Once you have done so about 30 times, place one deck of cards in the discard tray and all the numbered papers back in the container you are using to pull them from. Restart the process but this time, divide the number you pull by five (five decks on the table). Continue this process until you have worked your way through all decks. These practices should help you master the art of card counting. You can also practice calculating the true count by doing simple divisions while jogging or relaxing. It is essential to get these basics right before attempting to try them out in real games!
FAQ
Is it legal to count cards in blackjack?
No, while it is frowned upon, no law states that it is not allowed. The US and British laws do not prohibit card counting. The casinos, however, strictly prohibit players from using any external card-counting device or person to assist them in counting cards. In general, casinos oppose card counting and try to prevent it. Often, they ban suspected card counters from playing in the casinos. Some casinos, especially in Nevada, strictly prohibit the use of card-counting apps and devices.
How do online casinos minimize card counting?
Online casinos complicate the process by adding more decks. Consequently, it is more difficult to identify the concentration of high and low cards left in the shoe. Casinos may also use Continuous Shuffling Machines, which makes it impossible to count cards when playing blackjack.
Does card counting work in online blackjack?
Yes, you can count cards when playing blackjack online against live dealers. If you want to know how to count cards in online blackjack, you can apply all the systems and strategies we’ve explained in this article. It is important to note that counting cards in online blackjack is not as profitable as doing so at land-based casinos due to several reasons, but more specifically, the pace of online blackjack games.
Can team card counting strategies increase success rates in blackjack?
Yes, it absolutely can increase success rates to play in a team setting. What could be especially beneficial from team card counting is an increase in the Expected Value or profit that can be earned, as this increases with the addition of shares in the overall bankroll. More players also reduce the risk.
What are common beginner card counting mistakes?
Among the many mistakes beginners make, not applying basic strategy is the biggest. Next is overbetting and not managing their bankroll effectively, and last but not least, making insurance bets thinking that it could have a positive outcome when there is a 70% chance that it won’t.
Use these Blackjack Strategy Charts to learn the correct decision for every hand. Basic Strategy is the first step to beating blackjack with card counting
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