How to count cards in Blackjack

By Ville Saari. Updated: 2024-02-23T09:31:56+0000

Learn how to count cards in blackjack. Counting cards is a skill you can learn to become a better blackjack player.

Here on Bojoko, we will teach you how to count cards, what different counting strategies are available and how to use that skill on an actual blackjack table.

Card counting gives you a better chance of winning and can even turn the odds in your favour.

What is card counting?

Card counting is a process where you keep track of the cards played so you know what is left in the deck. You don't count individual cards but rather keep track of the number of high and low-value cards that have been played.

When you know a deck is hot or cold, you can adjust your wagers accordingly.

Blackjack card counting is a way for the player to improve their chances. A good card counter can take the casino's edge and turn it around. With practise, a skilled card counting blackjack shark can gain up to a 3% edge over the casino.

Card counting is perfectly legal, but casinos frown upon it. If a player is suspected of counting cards, they will be stopped, barred from playing in the card rooms or even banned from the entire casino where that is possible. Casinos have countermeasures to prevent counting and will actively keep an eye out for card counters.

But before you start counting cards, you should first learn how to play blackjack. Check out our how to play online blackjack page for a comprehensive guide.

Origins and history of card counting

The history of card counting as we know it today dates back to the late 1950s and early 1960s. This was the post-war boom years and when Las Vegas became the epicentre of American gambling.

When gambling became an everyday thing, people wanted to get good at it and beat the casino. While most games were purely random, blackjack gave the player some control. Mathematicians and mathematically inclined gamblers realised that they could count the cards played to know what values were left in the deck and knew how this affected the gameplay.

Edward O. Thorp is considered the father of modern card counting. His book, Beat the Dealer, goes over the betting strategies for optimal play. Over the years, casinos have taken more countermeasures, and many of Thorp's practices are no longer applicable. The core for card counting was there, even if it was rudimentary.

Players like Joe Bernstein, Harvey Dubner, Roger Baldwin, Wilbert Cantey, Herbert Maisel, and James McDermott all created or improved the techniques to beat the casino and let players gain the edge. Methods like Hi-Lo counting were introduced, and concepts of true count for multiple decks were helping perfect the strategies.

Most of the basic concepts of modern card counting were invented early on. The later years have been more about honing the actions, and casinos and players one-upping each other with countermeasures and counter-countermeasures.

Blackjack card values

To start counting cards, you need to know the blackjack card values.

Here are the values of different cards:

Cards 2-10: The card number is the value
Jack, Queen & King: All are worth 10
Ace: It can be either 1 or 11, whichever is better for you

Values of the cards played in blackjack

Card value is the key factor in card counting. You need to keep track of how many low, medium and high cards have been played so you know what is likely to come next.

If the deck has a lot of small cards left, it is better for the casino. A deck full of high cards gives you more blackjacks, which pay out more, and the dealer is likelier to go bust when hitting a high card.

Losing to a dealer's blackjack is a 1:1 loss, but winning with a blackjack pays 3:2. This way, even an equal number of blackjacks for you and the dealer is positive for you.

When counting, a deck with a lot of low values is called a cold deck, and a deck with high cards is a hot one. The term cold deck is also used for a stacked deck which is allegedly used when players are running hot.

Hi-Lo card counting

Hi-Lo card counting is the most common card counting method for blackjack and the easiest to learn. It keeps a count of high and low-value cards that have been played.

Simply put, when a low card is shown, you add 1 to your count, and when a high card is shown, you take away 1. At the end of a single deck, your total should always be 0.

If your running total is high at any point, you can tell that the deck has more high cards left, and you should bet more. If the total is low, then you bet less or even walk away.

You should learn the basic strategies before going too deep into card counting. You can read about them on our basic blackjack strategy page.

Card count and values

blackjack HiLo card counting

Hi-Lo count is based on the following rules:

+1: Cards from 2 to 6
0: Cards from 7 to 9
-1: Cards from 10 to ace

The Hi-Lo card counting strategy is known as a "balanced system" where the sum of all cards in a 52-card deck is 0.
EXAMPLE: You're dealt 10 and 7; the dealer is showing a 6. You stand, the dealer reveals an Ace, and you push. What's the count?

10 = -1
7 = 0
6 = +1
A = -1
Final count = -1

The running count

The running count is the raw number you get when you count the cards over multiple hands. It does not take into account the number of decks used; it just counts the high and low cards.

Doing a running count means that you start counting the played cards and keep track of the numbers that have come up so far. This is something you can practice by doing card counting drills.

It is better to get a running count going immediately after a casino picks up a new shoe. Then the count is going to be more accurate. Missing out on a half-a-deck's worth of cards can make your running count inaccurate from the actual state of the shoe.

True count

The true count is the total running count divided by the number of decks used. It adjusts the score to what it would be if you only used a single deck.

True count = Running count ÷ decks remaining in the shoe

The true count is used in some strategies when deciding what actions to take at what point of the game.

Advanced systems based on the Hi/Lo counting

Using advanced counting systems that are based on the Hi/Lo counting can give you even better results.

These strategies may be more difficult to remember and use but can lead to what some call the perfect blackjack strategy.

The Fab Four is a method that uses Hi-Lo to keep a true count and then has additional instructions on when to surrender for maximum value.
The Illustrious 18 is an advanced system with 18 game decisions depending on the count and situation. This is a very difficult system to remember, but is easier online with a cheat sheet.

If you are already good with Hi-Lo counting, you can give these systems a try. They increase the difficulty but also improve your bottom line.

Other blackjack card counting systems

Bojoko teaches you card counting in blackjack

Here are some other blackjack card counting systems than Hi-Lo. Some of these are even easier to learn.

Other counting systems are often unbalanced, meaning the final count of a 52-card deck is not zero. What makes things easier is that true count is not necessary with them.

The Key Card Count

Key Card Count was designed by Fred Renzy, and it counts only a handful of cards.

All 4s and 5s are +1
All 10s are -1.
All black Aces are -1 (by choosing black aces, you're counting exactly 50% of the aces in play as -1)

This is an unbalanced system, and the total sum of a deck is +2.

You start the count when the deck is shuffled at +18. When you spot a 4 or a 5, add one to your count, and when you see a 10 or a black ace, reduce your count by one.

Based on the count:

20 or more: Increase your bet
19 or less: Reduce your bet or bet the minimum

The Red 7 Count

The Red 7 Count was created by Arnold Snyder, and this system counts the following cards:

All low cards and red 7 are counted as +1
All 10s, face cards and aces are counted as -1

This is also an unbalanced system with a total sum of +2 for each deck.

You start your count at -2 for every deck in the shoe. So, if you use 6 decks, you start at -12.

When the score reaches zero or goes to a positive number, you should raise your bets. At this point, the deck is favourable to the player.

Card counting online blackjack vs land based

Card counting is different in online blackjack and land based casinos. The basic skills are the same, but how you use them differs.

The important thing to know is if card counting is even possible. Regular RNG online blackjack shuffles the deck after every hand, which makes counting pointless. A land-based casino may also use continuous shuffling machines, which work the same way. Always avoid these tables.

Land-based casinos will be noisy places with a lot of distractions. This will make focusing on your count difficult. It is also possible that the dealer will actively try to engage you in conversation to mess you up if they suspect you are counting.

If you can handle the distractions and even chat while counting, land-based casinos are better places to use your card-counting skills. They go through more cards without shuffling, or in other words, penetrate the shoes deeper. This makes your count more accurate. On the other hand, if a casino suspects that you are counting cards, they will most likely throw you out.

The best thing is to find a good casino from our blackjack sites page and head to their live casino table. There, you can count cards in peace.

Practise card counting

You can practise card counting here on Bojoko with our blackjack simulator and card counting drill.

You can check the card counting drill and try counting on our free blackjack simulator.

Card counting is a skill, and just like every other skill, you can practise it. The more you do it, the better you become at it. And we have created the tools for you to do just that.

Practise your running count first, and then test your skills on an actual free-play blackjack simulator. This simulator is designed for practising card counting and will not continuously shuffle the deck.

If you want to practise on your phone or tablet, you can download our free app.

Free blackjack trainer for Android
Free blackjack trainer for iOS

Pros and cons for card counting in online blackjack

There are pros and cons of card counting in online blackjack. Below, you can see if online card counting is good for you.

Pros

✅ You can use physical tools and software to help you
✅ No one is trying to distract your count
✅ You can't be thrown out for counting cards

Cons

❌ Counting against RNG blackjack is impossible
❌ Live dealer casino deck penetration is low
❌ Some live casinos still use continuous shuffling machines which can't be counted

FAQ

Card counting means that you keep track of which kinds of cards have been played, so you can better estimate what cards will be left in the deck. It is better for the player if the remaining cards have more high-valued cards than low-valued ones.

It is not illegal to count cards in blackjack. It is a genuine skill that you can learn, and not cheating in any way. There are no laws that say you can't count cards in a casino, be it online or offline.

Many brick-and-mortar casinos treat card counting as a forbidden practice, as it increases the player's chances significantly. Privately owned casinos can legally refuse you access to their card rooms if they suspect that you count cards.

You count cards in blackjack by making a note of the card numbers that have been played. This way, you can better know which cards are left in the shoe and when is a good time to bet more aggressively.

Card counting looks at the card's values and keeps a running count on how many low and high cards have been shown. If most of the high numbers have been played, the cards left are not optimal for the player and vice versa.

Hi-Lo card counting system is a basic method of keeping track of the played cards and, thus, seeing what kinds of cards are left in the deck.

The idea is to increase the count if a small card is played, keep it unchanged for medium cards and decrease it for any high-value cards. As large cards are better for the player, you know when the deck is likely to have good cards left.

When the count is high, you change your bets and wager more money. When the count drops, you reduce your bets or even walk away.

Yes, counting does work in blackjack. Casinos do their best to combat this, but a good card counter can take the edge.

Playing with a perfect basic strategy reduces the house edge to roughly 0.5%, but counting cards can make it so that the player has a 1-3% edge over the casino. This depends on your skill level, the counting method used and the countermeasures the casino takes.

To learn card counting usually takes around 2-4 hours of practise. Being able to hold a simple running count is a fairly quick thing to learn. Getting good at holding a true count in a noisy environment takes about 20-40 hours of practise.

Learning more complicated calculations, remembering all of the optimal game actions and being able to apply them to real life can take up to 150 hours.

A lot of this depends on the person who is doing the learning. Some people will grasp it quickly, while others might struggle with keeping an exact running count.

Yes, card counting is good for your brain as a way of improving your mental acuity. All puzzles and mental challenges can keep your brain healthy and sharp for longer.

Card counting requires quick thinking, and you need to keep track of running numbers. Both of these are great features of any brain exercise puzzle.

Hi-Lo is the best card counting system for most players. It is easy to learn, and most people can handle keeping a count even when the games run fast or long.

If you are good at card counting, then there are even better options available. They are all based on the Hi-Lo counting principle but include more game actions. The Fab Four includes four instructions depending on the true count. The Illustrious 18 has a total of 18 game decisions to remember. These can get better results but require more concentration and skill.

It is profitable to count cards if the casino is suitable for it. This means that if the casino takes effective countermeasures against card counting, for example, using an excessive number of decks or hiding the number, successful counting becomes difficult.

A skilled card counter can turn the odds heavily in their favour. When this happens, the casino staff will take notice, and it is possible that the pit boss will escort you out of the casino and may even ban you.

Blackjack card counting was invented by an American mathematician Edward O. Thorp. He outlined the betting strategies and optimal play, though some of his techniques are no longer valid. As counting became more prevalent, casinos took measures that counteracted them.

There have been other mathematicians and professional gamblers who have either created their own ways or perfected the methods Thorp came up with. Jess Marcum, Joe Bernstein and Al Francesco can all be credited as card counting inventors.

About the author

Article by:

Ville Saari

Ville is an industry veteran, who has written thousands of gambling-related reviews and articles since 2009. He is an IT engineer with a passion for game and strategy optimisation, and to teach the world to play better.