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How to count cards when playing Online Blackjack

Published by Niki | December 21, 2021 | Last updated: April 18, 2023

Made famous by films such as 21, card counting in Blackjack is a learned skill that intrigues casino players and has done so for many years.

Some of the best card counters in the world have managed to win millions of dollars by tracking the high and low cards left in a dealer’s deck. It may sound too simple to be effective but learning the art of card counting can take years to perfect.

As the world embraces online casinos more openly, the questions remain: Is it legal to count cards? And is it possible to do so when playing Blackjack online?

How to count cards when playing online Blackjack?

What is card counting?

Card counting is an online gambling technique that requires tracking the cards that are dealt at a blackjack table. Having the ability to track the number of high and low cards left in a deck can swing the outcome in your favour, should you place a smart bet.

For those who manage to count cards successfully, knowing when to place the perfect bet could mean more significant wins can be landed. However, it should be noted that card counting on its own is not the key to winning (or cheating) when playing a game of Blackjack – it is simply a skill that can be learned and honed.

You may be wondering if card counting is legal. It may feel illegal, but there are no laws against card counting. This is only the case if you’re counting in your head and not attempting to use a physical machine or app to do the counting for you. This can be seen as an unfair advantage that online casinos frown upon.

While there are no laws against card counting, casinos are generally not okay with it, and they may ask you to leave if you’re a suspected card counter. But when you’re playing online, it’s a whole other matter…

Can you count cards when playing Blackjack online?

The short answer is yes – you can count cards when playing Blackjack online, but it may not be as easy as doing so at your favourite brick and mortar establishment. One of the main reasons that counting cards when playing online is tough is that the game software automatically shuffles the deck after each hand is dealt.

Quick fact: A typical card counter who ranges bets appropriately in a game with 6 decks will have an advantage of approximately 1% over the casino. This is up from the usual 0.5% house edge that is usually available.

While the shuffling of the deck may make it harder to keep track, it’s not impossible. One of the most significant advantages of playing online from your home is that you can count cards openly by making notes or talking out loud without the risk of being scrutinised or being asked to leave the casino.

Playing free Blackjack online casino games is the perfect way to practice and experience the possible difficulties of counting cards online. You can learn more about Blackjack in our online Blackjack basics guide

Crash course: How to count cards in Blackjack

It doesn’t matter if you choose to play Blackjack online or while seated at a table in the middle of a land-based casino, counting cards have a certain rhythm and strategy to it that must be mastered to succeed.

You’ll start by assigning each of the cards that are dealt by the dealer a specific number. All of the 2 to 6 numbered cards are given a value of +1. If numbered cards ranging from 7 to 9 are dealt, they receive a value of 0. And finally, any card that is a 10 card or a face card will receive a value of -1.

Now that you’ve assigned the cards a value, it’s vital to keep track of the score that remains in the deck. A running tally of the cards that are dealt will help. If you’re playing at a land-based casino, you’ll need to keep this tally running in your head. However, play at an online casino from home, and you can easily keep track of the numbers by writing them down or typing them into your phone.

We have already prepared a comprehensive guide for you to learn more what is the difference between land-based casinos and online casinos.

Top tip: There are apps and software that exist which will do the card counting for you, but these are frowned upon and often seen as cheating – even when playing from home.

As soon as you’re comfortable with how the numbers are leaning in the deck, you can adjust your betting to match. If the count you have for the remaining cards is negative, it may be a good idea to increase your bet size. This is due to the fact that many low-value cards are left in the deck. The opposite applies too. If the remaining deck is in the positive (and is therefore filled with a majority of high-value cards), decrease the size of your bet accordingly.

This basic strategy used for counting cards is referred to as a Hi-Lo strategy.

4 easy steps for counting cards

There are many skills involved when counting cards, but starting at the very beginning is the simplest way to learn. These are the most straightforward steps to keep in mind, and they will help you on your way to learning more about card counting in no time at all.

  • Step 1 – Assign a value to each card that is dealt (+1, 0, and -1 are the most common)
  • Step 2 – Keep track of the card values as they are dealt
  • Step 3 – Keep a running count of the cards by adding the card values together. This will help you determine the value of the cards left in the deck.
  • Step 4 – Place your bets according to the card count remaining in the deck. If the card count is negative, increase your bet. If the card count is positive, decrease your bet.

These steps may be straightforward, but they are the base for every card counting strategy worth its salt. You could even develop your own strategy to help you on your way as you learn and better understand the card values.

Quick overview of card counting strategies

If you feel that you’ve mastered (or are on your way to mastering) the Hi-Lo strategy, learn more about the more advanced card counting strategies that exist too. While these strategies may be slightly more involved or intricate, they could suit your playing style more than the standard Hi-Lo version.

  1. Omega II – This is often referred to as the “balanced system”. You start with 0 as your base and assign different card values to different sets of cards. The values include 1 for cards 2, 3 and 7. A value of 2 is assigned for cards 4, 5 and 6. Assign -1 to the 9 cards, -2 to the 10 card and all other face cards, and finally, a value of 0 is assigned to the 8 and Ace cards. Keeping track of this strategy can be tricky. It was originally developed by Bryce Carlson who released a book about card counting.
  2. Group Play – Rather than just rely on your own brainpower to see you through, there are groups of players who use teamwork to count cards at land-based casinos. The entire team will count different sets of cards and signal to each other when the right time to bet is. This is what the film 21 is about – a story that was based on a real group of card counters from MIT.
  3. Wong Halves – Created by Stanford Wong, this is considered an advanced strategy thanks to the exciting values that are assigned to different cards. Some of the assigned values are fractions which means you’ll need to be a maths whizz to keep track of the running tally with ease. Also referred to as a “balanced system”, the base of this strategy is 0. This means that when the deck of cards is completely dealt with, the remaining value should be 0. When using Wong Halves, the values for the cards are 1 for cards 3, 4 and 6. Count 0.5 for the 2 and 7 cards. When a 5 is dealt, the value is 1.5. If an 8 is dealt, 0 is added to the tally. When a 9 card is dealt, the value is -0.5. Finally, a -1 value is attached to the 10, Ace and face cards.
  4. Multiple Decks – While the students in the movie 21 used group play to achieve their goals, the group used the Multiple Decks strategy to win millions. Casinos use multiple decks to try and dissuade players from counting cards or, at the very least, succeeding in doing so. The best way to work around the use of multiple decks is by using the Hi-Lo strategy, and then you will need to divide the running total you have in your head by the number of decks that remain. Referred to as the ‘true count’, a 100% accurate running tally must be kept for this to work as it should. If your count is off and you divide it by the remaining number of decks, your true count will be off by much more than it would be if counting through a single deck.


If you’re not sure which strategy would suit you best, it’s possible to test each one for the pros and cons based on your way of playing. Use free versions of Blackjack online before betting with real money.

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