How to Count Cards in Blackjack

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Level: advanced

9 m mins read

Page updated 22 July, 2021

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Mr Blackjack

Mr Blackjack is Matt Blake, founder of Never Split 10's on YouTube, where he entertains and educates gamblers on the gameplay and basic strategy behind 21.

Country Canada

Taught blackjack for 9 years

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What is Card Counting in Blackjack?

Card reading helps players determine who will have the probable advantage in the next hand in blackjack by keeping a tally of low and high-value cards in the game.

Many players have a perception that card counting requires a genius level of intelligence. In reality, card counting strategies vary in difficulty. Some basic card reading strategies use a simple tally system that anyone can do. Advanced counting systems have complex point values that give players greater accuracy but require precise calculations.

How Does Card Counting Work?

Card counting helps players increase their bets at the right time in real money blackjack games and minimize their losses during cold streaks.

Card counters (also known as advantage players) use card reading to change their plays depending on the composition of cards left in the dealer’s shoe. All these factors combined help players reverse the casino’s edge in blackjack. In essence, card counting works like this:

A player assigns a negative, positive, or zero value to face and number cards.
They maintain a ‘running count’ based on the cards dealt in the game.
Once they feel confident of the ‘true count’, a player can alter their bets depending on their advantage.
As fewer cards are left in the shoe, the player improves their true count and makes more decisive wagers.

You need patience, lots of practice, and attention to detail, but anyone can learn this blackjack strategy. Given card counting is one of the most effective strategies to winning at blackjack, it is worth your time and effort.

Basic Blackjack Card Counting Strategy

Learn the Most Popular Card Counting System - Hi-Lo

SEASON 6 / LESSON 3

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Blackjack card counting strategies don’t come any easier than the Hi-Lo system. This is the simplest and most popular strategy to learn, ideal for newer or casual blackjack players.

How to Count Cards in Blackjack with the Hi-Lo System

The Hi-Lo system breaks cards into three camps, each with a specific value:

Hi-Lo Count Value Levels

Value System	Card Types	Value
High Cards	10, J, Q, K, A	-1
Neutral Cards	7, 8, 9	0
Low Cards	2, 3, 4, 5, 6	1

High cards are good for players, but they get a -1 value because the fewer high cards are left in the deck, the more a player’s advantage decreases. Low cards are beneficial to the dealer, which is why they get a +1 value. 7s, 8s, and 9s don’t benefit the dealer or the player, so they get a value of 0.

The Hi-Lo strategy is called a ‘balanced’ counting system because of the combination of High, Neutral, and Low cards in a deck equal to zero.

Using these metrics, the Hi-Lo system requires you to calculate a running total of all cards played in the game, including the dealer and other players’ hands. This is called the ‘running count’. Let’s run through an example of Classic Blackjack to explain:

Hi-Lo strategy begins once the dealer introduces a new shoe to the table. At this point, the running count is 0, because no cards have been dealt yet.
Depending on the blackjack game, the cards will be dealt in a particular order around the table. From here, you must look at the cards dealt so far and calculate the ‘running count’.

Based on the cards in the picture and Hi-Lo’s metrics, we know Player 1’s hand equals 0, and the same goes for Player 2. Player 3 has a Jack and an Ace, which equals -2. This gives us a running count of -2 so far.
As players make more moves in the game, you should add these cards to your running count.
Let’s say Players 1 and 2 decide to hit. Player 1 receives a 6, which brings the running count to -1 but Player 2 is dealt a 4, which also has a value of +1. Player 3 stands. This brings your current running total to 0.

Now we’ll add the dealer’s cards. The dealer has a 5 up-card and turns their hole card, which is a King. Added together, these have a value of 0, meaning our running count remains unchanged.

The dealer decides to hit and deals themself a 4. This is a low card, worth -1. The dealer stands, which gives you a running total of -1 by the end of the round.

As the running count increases in blackjack, so does the player’s advantage. This is when you should increase your bets. As the running count decreases, the casino has the advantage. You should lower your bets to minimize your losses.

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You can quicken your card counting using the Meaningful Pairs technique, as popularized by MIT Blackjack Team member Mike Aponte. Instead of adjusting your calculations on each card as it appears on the table, calculate the running count in pairs. You’ll soon find many pairs ‘cancel’ each other’s count, thereby reducing the number of calculations you must make.

What is ‘True Count’ in Blackjack? How Does it Affect Card Counting?

Card counting may sound easy so far, but online casinos complicate the system by adding more decks to the game. This makes it harder to identify the concentration of high and low cards left in the shoe. Players will struggle to make accurate bets on their running count because their advantage in six or 8-deck blackjack games is skewed compared to single-deck 21.

This calls for another step in the Hi-Lo system: the ‘true count’. This calculation tells the player their advantage at any point in a multi-deck blackjack game. To convert your running count into the true count, simply divide your running count by the number of decks remaining in the game, rounded to the nearest half-deck.

True count = running count / decks remaining

Let’s look at another example:

You’re in an 8-deck blackjack game, with a running count of +7 so far. You realize there are roughly four decks left in the shoe, which gives you a true count of +1.75, or 2 when rounded up.

As the true count increases, so does your advantage. Players should bet proportionally more as their advantage increases and decrease their wagers to as little as possible when the house has the advantage.

How Much Should I Bet When Counting Cards?

Betting styles and sizes in card counting depend on a variety of factors: bankroll size, a player’s appetite for risk, blackjack rules, and betting strategies. Older gambling guides recommend specific betting patterns in card counting, but many casinos are aware of these already and use them to fish out card counters.

Here’s a simple equation many players use to determine how much they should bet when card counting:

Betting amount = true count – 1 betting unit

If you had 1 betting unit worth $10 and a true count of +3, then your betting amount would be $20. This is because 3 – 1 = 2, and 2 betting units equals $20.

This system is basic, but it helps you bet proportionately and stay within your betting limits.

How to Count Cards with 1 Deck

Using the Hi-Lo system above, players only need the running count to assess their advantage in single-deck games. True count isn’t required. That means you can spend more time applying basic strategy to your card counting.

Single-deck blackjack games are great for new card counters. They give the best odds for players, and it’s easier for beginner counters to track their advantage when fewer decks are involved. Plus, the house edge is a mere 0.16% in single-deck blackjack.

Online casinos are aware of these factors and will sometimes add restrictions to single-deck blackjack games to tip the odds in their favor. Limiting re-splits or letting the dealer hit on a soft 17 are common rules that restrict a player’s moves, and consequently their winnings.

How to Count Cards with Multiple Decks

With any balanced counting system like Hi-Lo, players must convert their running count into the true count when playing multi-deck blackjack games. The true count ensures every card counting system can be used in blackjack, regardless of the number of decks in play. This helps you adjust your bets to your advantage, and assess how many high-value cards are left in the shoe.

Tips for Mastering Card Counting

Card counting systems can be simple, but some players struggle to keep count when they combine it with basic strategy. To be successful, you need to practice until card counting becomes automatic. Try out the exercises below.

Take a single deck of cards and keep a running count through all the cards.
Remove one card from the deck and keep a running count; you should know what card value you removed by the end.
Time yourself — the more cards you can count accurately within the same period, the more your card counting skills will improve.

Advanced Blackjack Card Counting Strategies

Hi-Lo is good for beginners, but players wanting more precision in their card counting should learn the Omega II and Wong Halves systems. These Level II and Level III systems in card counting are for intermediate and expert players respectively and require greater accuracy for success. While more complex, these systems offer players greater betting efficiency in blackjack.

How to Count Cards Using the Omega II System

Unlike Hi-Lo, which bases its count values across +/-1, Omega II forms its values across +/-2, making it a multi-level system. This means players must calculate additional values to reach a running count.

Omega II Count Value Levels

Cards	Point Value
4, 5, 6	2
2, 3, 7	1
8, A	0
9	-1
10, J, Q, K	-2

In Omega II, players keep a running count using the same method as Hi-Lo. Omega II is a balanced card counting system, just like Hi-Lo, meaning the shoe starts at 0 and players will also have to calculate a true count in multi-deck games. The formula for determining true count is the same for Omega II. Players just need to divide their running count by the number of decks left in the shoe.

Omega II’s value levels give you greater accuracy in determining your advantage based on the true count. This helps you make bets that are more proportional to your advantage and make better moves on blackjack deviation strategies. The trade-off though is that you must be exact in your counting, otherwise you lose any benefit.

Count value aside, Omega II has one other rule. Players must also keep a side count of Aces dealt in the game, too. This count helps players determine the number of Aces left in the shoe, and consequently their chances of getting blackjack.

How to Count Cards Using the Wong Halves System

Wong Halves is the most complicated card counting system in blackjack. Like Omega II it’s a multi-level system, but it uses three value levels. Only players that have already mastered another card counting system should give Wong Halves a try — this system can break beginners.

Wong Halves Count Value Levels

Cards	Point Value
5	1.5
3, 4, 6	1
2, 7	0.5
8	0
9	-0.5
10, J, Q, K, A	0

Unlike other card counting strategies, Wong Halves uses fractions in its values. This makes card counting very difficult for players, especially considering the various distractions in a blackjack game.

The flipside though is that Wong Halves is extremely accurate in predicting the player’s advantage. It has a 0.99 betting correlation out of 1.00, meaning it is nearly perfect when it comes to predicting good bets.

To count cards using Wong Halves, keep a running count of cards in play, just like you would in any other card counting system. Wong Halves is a balanced system, so players need to start their count at 0 whenever the deck is shuffled and incorporate true count into their strategy.

With betting in Wong Halves, you should increase your wager size when their true count increases. Likewise, you should reduce them to as little as nothing when the dealer has the advantage.

Betting styles in Wong Halves can also vary. Some players multiply their true count by the minimum bet limit at the table to determine their bet size. Others subtract one betting unit from the true count to decide how much they want to wager. It depends entirely on the player and their betting style.

Which Card Counting System is the Best for Blackjack?

This depends entirely on a player’s accuracy and dedication to practice. Level II and Level III systems like Wong Halves require perfect calculations from players to work. Otherwise, the accumulation of small errors made across these advanced counting systems can erase any profit players make.

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For most, the Hi-Lo system is simple enough to grasp and it has a positive influence on their gameplay. When combined with basic strategy, Hi-Lo helps players make smarter bets and moves in blackjack.

Live Online Blackjack Card Counting

Any searches online for ‘card counting’ and ‘live blackjack’ generate passionate and often conflicting advice. The truth is that while card counting in live blackjack is possible, it is very difficult. Online casinos use several methods to reduce or erase a card counter’s advantage in live blackjack, including:

Continuous Shuffling Machines (CSM): These devices continually shuffle decks, making card counting impossible for players.
Deck Penetration: Some online casinos replace 8-deck shoes once 50% of the cards have been played, meaning card counting is ineffective.
Rounds Per Hour: Live blackjack games are slower, which limits the number of hands played and the card counter’s overall winnings.
Blackjack Rules: Variations like 6:5 payouts or the dealer hitting on soft 17 can increase the house edge so much it voids card counting.
Card Scanning: Dealers sometimes scan cards before adding them to the table. Backstage, the casino’s systems will analyze players’ betting patterns and the table’s cards to identify any counting.

If you want to play live blackjack, look for online casinos that pay 3:2 for blackjack, like Betway or LeoVegas. Find tables where the dealer manually shuffles cards or uses machines like batch shufflers. Depending on deck penetration, these systems will still enable you to count cards. Finally, look for live games with favorable blackjack rules for players.

Blackjack Card Counting Apps

There are over 100 different card counting apps for blackjack available for Android and iPhone, but users should beware. Some of these apps offer features that will count cards for you in real money blackjack games. This is illegal in the US, as assistance from an app is considered cheating. Casinos are in their right to ban you and withhold winnings if you’re caught using these apps in real money games.

Blackjack card counting apps for practice however are perfectly fine. Check out our recommendations of the best blackjack apps to help you become a blackjack expert.

Learn Basic Blackjack Strategy

Don’t even consider card counting at the casino if you haven’t already memorized basic strategy. It’s impossible to win at blackjack by card counting alone, and basic strategy gives the statistically best move for players for any hand scenario in 21.

With basic strategy, players decrease the casino’s 2% edge to 0.5%. Card counting only gives players a 1% profit margin, meaning any benefit is immediately lost if gamblers forego basic blackjack strategy.

Understand Basic Blackjack Rules

The type of blackjack game you play can heavily influence your odds of winning at 21. Some games, like Blackjack Switch, see the dealer push on 22, which decreases a player’s expected return in the game by nearly 7%. Here are just a few ‘good’ blackjack rules players should look out for:

Double down after splitting pairs
Re-split aces
Players can join a game mid-shoe

Discover which games of 21 offer players the best terms with our blackjack rules guide.

Is Counting Cards Illegal in the US?

Card counting is not illegal in any local, state, or federal laws in the US. If a player receives assistance counting cards from a device or another player though, then this is illegal. Casinos are also private establishments and reserve the right to ban card counters they believe are winning too much money from the table.

Blackjack Card Counting Myths

Hollywood hits like 21 and Rain Man may have popularized card counting, but they’ve also spread several myths about this casino game strategy. Find out whether there is a grain of truth to the most popular card counting theories spread by casual and experienced players alike:

Card counting requires a mathematical brain for memorizing cards – FALSE. Card counting systems like Hi-lo require you to keep a basic tally in your head. With some practice, many card counters can keep score while simultaneously chatting to other players.
You are due a win – FALSE. Each hand is independent of one another in card counting. Players are never ‘owed’ a win from the cards. If you’re making risky decisions based on how much money you’ve lost, you’re tilting and should leave the table.
Players can ‘get rich quick’ counting cards in blackjack – FALSE. Card counting requires dedication and energy to master, not to mention knowledge of casinos’ tricks to discourage this strategy. Players can also spend hours counting cards before they have an advantage.
Other players’ mistakes will cause you to lose – SOMETIMES. Sure, there are times new players ignore basic strategy and make moves that give the dealer the better hand. It’s been mathematically proven that the opposite happens equally often. There’s no evidence that errors from other players affect your long-term outcome, so shake it off and focus on your next hand.
Card counters never lose – FALSE. Variance in blackjack means card counters lose often. Skilled card counters though understand how expected variance works and bet strategically when they have the advantage in blackjack.