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How to Count Cards in Blackjack – Make Your Game Count

Card counting is a technique used in blackjack to improve your long-term odds. By assigning values to each card, you can gauge the strength or weakness of the remaining cards in the show.

Adjust your bets depending on the value of the remaining cards. Your bets increase if the count is high. You decrease your bets if the count is low. That’s really the core principle behind counting cards.

Card counting is an easy concept to learn. Here, we’ll show you how to count cards in blackjack, and teach you a few systems to beat the house. We also have a blackjack trainer to help you practice online.


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What is Card Counting?

Card counting is a method used by blackjack players to get an advantage over the casino. Essentially, counting cards in blackjack involves assigning values to every card dealt out. By keeping a running count, you can assess whether the cards still to come will be high value or low value.

The player continues to add to the count for every card dealt, including the dealer’s cards. The higher the running count, the more you bet. The lower the count, the less you bet. It’s that simple.

In land-based casinos, dealers use automatic shufflers once the shoe runs out. Once the shoe is refilled, you reset the count and start again at zero.

This is one problem when it comes to card counting online. Most online blackjack casino games use shufflers after every hand. However, you can try to count cards in live blackjack games, where real-life cards and shoes are used.

Before you learn how to count cards in blackjack, you’ll need to learn the basic rules. You will find a detailed guide to playing blackjack here.

How to Count Cards

What is card counting? It’s a simple blackjack strategy that can lower the house edge in the long term. Here’s how it works:

Counting with Multiple Decks – What Changes?

It’s quite easy to calculate the running count in single deck blackjack. But over time, casinos have wised up to card counters. In reaction, they started introducing multiple decks. That made it harder for card counters to work out what cards were left.

At a blackjack table using multiple decks, you need to adjust your count. In fact, you need another type of count for multi-deck games, known as the ‘true count’.

The true count is worked out using this formula:

True Count =
Running Count
Number of Unplayed Decks in the Shoe


You’re playing Classic Blackjack with 6 decks. Your running count is +4. There are 2 decks remaining, so our True Count is +4 / 2, or +2.

In the casino, you can get an idea of how many unplayed decks are left by looking at the shoe (if it’s made of Perspex), or by looking at how many cards are in the discard pile.

Generally, the higher the true count, the better it is for the player. When there is a True Count of +1, the player has little or no edge. With a true count of +2, the player gains an edge of 0.5%, and so on.

Now you know the true count, you can adjust your bet size. The higher the true count, the higher your bet. In fact, you should be doubling your bet every time the true Count goes up by +1.

So, what if the true count is +1 or lower? That’s easy – simply stick to your original unit stake. Keep doing this until the count changes, or the decks are shuffled and you begin again.

Now look at our table for sizing bets. It’s quite different to the table when following just the running count.

True Count Bet Size (units)
+1 or less 1
+2 2
+3 2
+4 3
+5 3
+6 4
+7 4
+8 or more 5

Why Count Cards in Blackjack?

Card counting is simple to learn, but it can take many years to fully master. So, what are the advantages of counting cards?

There are several advantages to using good card counting practice. These include:

  • Your chances of a natural blackjack increase. A blackjack pays 3/2, the best payout in conventional blackjack games.
  • As a player, you know when to double down and increase your returns.
  • The 2/1 insurance bet, normally a poor wager, suddenly offers good blackjack odds.
  • You can lower the house edge. The house edge goes down by around 0.5% when the true count is positive.

If you’re totally new to counting cards, then you probably have a few questions at the back of your mind. Here are some of the most common concerns that our readers share with us:

Knowing how to count cards in blackjack is pretty simple. You assign values to each card and keep a running count as you play.

The hard part comes in adjusting your bet size in real time and preventing the casino from catching you. Casino personnel are trained to look out for unusual betting habits that veer away from conventional 21 strategy.

A better question should be: is counting cards illegal? Under federal law, card counting is not illegal. However, it can be considered illegal if the player uses a card counting device or gains information from an accomplice.

That said, anyone caught counting cards will likely be banned from a casino for life. In New Jersey, casinos try to put off blackjack counters by shuffling the decks more often and using more decks.

The simple answer is yes. You need to standardize your bets enough so that the casino staff don’t spot anything unusual.

If you are sitting out when you should really be betting, or hitting when optimal strategy suggests you should stand, you will be spotted as a counter.

A good blackjack counter will go on losing streaks to throw off the casino personnel. But casinos oftentimes use former card counters to look out for and weed out anyone who may be counting.

Casino staff will look for tell-tale signs of blackjack counters, including:

  • Splitting 10s: This is almost never done in blackjack. But a card counter may split 10s if they know that high-value cards are left in the shoe.
  • Taking insurance after making a large bet: Optimal blackjack strategy is to never take insurance. But a card counter will have an idea when the dealer is likely to hit his blackjack. He will take insurance, even after risking a large bet.
  • Betting high at the end of a shoe: At the end of a shoe, a good blackjack counter will know what cards are left to come and bet high.
  • Unusual betting patterns: Optimal blackjack strategy is to keep bets standardized. But card counters will vary their bets a lot and even sit out from hands if the count is too low.

Blackjack Card Counting Strategies

If you’re new to counting cards, you may be surprised to know there are quite a few different strategies. However, each strategy revolves around assigning points to cards as they are dealt.

We’ve compiled the most common blackjack card counting systems for you.

Card Counting System 2 3 4 5 6 7 8 9 10, J, Q, K A Difficulty level
Hi-Lo +1 +1 +1 +1 +1 0 0 0 -1 -1 1
Hi-Opt I 0 +1 +1 +1 +1 0 0 0 -1 0 1
Hi-Opt II +1 +1 +2 +2 +1 +1 0 0 -2 0 2
KO +1 +1 +1 +1 +1 +1 0 0 -1 -1 1
Omega II +1 +1 +2 +2 +2 +1 0 -1 -2 0 2
Red 7 +1 +1 +1 +1 +1 0 or +1 0 0 -1 -1 1
Wong Halves +0.5 +1 +1 +1.5 +1 +0.5 0 -0.5 -1 -1 3
Zen Count +1 +1 +2 +2 +2 +1 0 0 -2 -1 2


Hi-Lo is the most common card counting system in blackjack. For cards 2-6, you assign +1. For 7-9, assign 0, and for 10-Ace, assign a value of -1. When counting cards with Hi-Lo, you change your running count as every card is dealt.

Hi-Opt I

The Hi-Opt I is a balanced card counting blackjack system. That means if you counted every card in the deck, the count would be 0. It varies slightly from the Hi-Lo count system in that any 2 or ace adds zero to the count.

Hi-Opt II

Hi-Opt II is a more advanced version of Hi-Opt I, developed by Lance Humble and Julian Braun. It assigns higher value to low cards like the 4 and 5 (+2 to the count instead of +1), and subtracts more (-2) for the 10, J, Q and K.

The Hi-Opt II is considered to be harder to implement than Hi-Opt I. But it’s also judged to be a more accurate and efficient counting system. That’s why many professional card counters use Hi-Opt II still.


The “Knockout Count” system is virtually identical to the Hi-Lo system, but any 7 adds +1 to the running count. You also adjust your starting count according the number of decks:

  • • 1 deck: Starting count of -2
  • • 2 decks: Starting count -4
  • • 3 decks: Starting count -8
  • • 4 decks: Starting count -12
  • • 5 decks: Starting count -16

Omega II

Omega II is very similar to Hi-Opt II in that it assigns higher values to low cards like 3, 4, 5 and 6. However, in this system, any 9 subtracts -1 from the count.

Red 7

The Red 7 system is easy to learn. It has identical point values to the Hi-Lo, but you add +1 to the count when you see a red 7.
You also adjust your starting running count depending on the number of decks. In this case, use the same starting counts as for the KO system.


The Halves, or ‘Wong Halves’, system is a difficult card counting system with complex point values.
Instead of whole numbers, you assign half-points to different cards. The Halves plan has been proven to be one of the most accurate counting systems in Twenty-One.

Zen Count

The Zen Count is a balanced counting system that is similar to Omega II. It’s a Level 2 system aimed at moderately experienced counters.

The Zen Count assigns a positive running count to low-value cards and a negative one to high-value cards. The values are staggered, so that 2 and 3 get +1, but 4, 5 and 6 receive +2. 10, J, Q and K receive -2.

Like the Hi-Lo system, aces are accounted for in the running count. You add -1 to the count when an ace appears.

You can try out any of the systems we’ve just discussed in our blackjack counter above. It’s the perfect risk-free way of figuring out which system suits you best.

How to Pick Your Card Counting Strategy

Knowing how to count cards in blackjack is the easy part. Choosing the right blackjack strategy is harder.

When deciding upon a good strategy at the blackjack table, you need to factor in these considerations, along with your own personal experience:

  • Playing Efficiency (PE):

    Playing Efficiency gives you an indication of your expected profit when using a blackjack strategy.

  • Betting Correlation (BC):

    Betting Correlation is used to calculate the total value of all the undealt cards. If the total is positive, a bet will offer you a positive return. BC is particularly important in blackjack games that use 6-8 decks. For example, the Hi-Lo has a BC of 0.97, while the Wong Halves system has a BC of 0.99.

  • Insurance Correlation (IC):

    Insurance Correlation is the amount you expect to gain when taking out the 2/1 Insurance bet. Assign -9 for tens and +4 for all other cards to predict whether the Insurance should be taken. The Zen Count offers one of the highest IC values of 0.85.

  • Level:

    Each card counting strategy is assigned a level. The Hi-Lo is a single-level system which is easy to put into practice. Level 2 and 3 systems assign more values to different cards.

  • Side Counts:

    Side counts can improve blackjack odds for experienced card counters. Side counts usually require you to adjust your count based on the number of aces or ten-value cards left in the shoe.

Back-Counting – Is it a Good Idea?

Back-counting is also known as “Wonging”, from Stanford Wong, one of the pioneers of blackjack card counting.

With back-counting, you don’t play at the blackjack table yourself. Rather, you observe the other players, counting cards as they appear. You then sit down at the table when the count is in your favor.

Wonging is a good strategy for blackjack at live dealer casinos too. You are allowed to watch a table before choosing when to take your seat. You have the advantage of saving your bankroll until the count is high enough to play.

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Counting Cards – Our Top Takeaways

Card counting isn’t for everyone. But if you want to learn how to count cards, follow these simple rules.

Be patient

Card counting won’t always go in your favor. You need to be patient and wait for the count to be high enough before making your big bets.

Disguise your bets

Casino staff and dealers are trained to spot card counters. Consider mixing up your bets to throw them off the scent. This might involve purposely losing a series of bets.

Practice with a blackjack counter or blackjack trainer

It’s important to practice card counting online before you hit the casino. You can find plenty of blackjack counter apps online. These apps train you to calculate the running count and true count. You could also use our blackjack trainer right here on our page, directly via your web browser.

Experiment with different strategies

No two card counting strategies are exactly alike. Start with Hi-Lo because it’s the easiest way to break the ice with card counting, but don’t be afraid to try out other methods that you might like even more.

Try free blackjack online

You can get plenty of card counting practice by playing free blackjack. Most online casinos have a Demo Play blackjack game where you can hit the tables with no risk.

Practice by playing live dealer games

Live casino blackjack still uses real-life cards and shoes, making it a great way to test out card counting strategies in real time. If you plan on card counting at land casinos at some point, then it’s a good idea to buff up your skills with live dealer games first.

Practice Card Counting With Our Free Game or Blackjack Trainer

You know how to count cards and apply different strategies. Now it’s time to put it into practice. Check out our online blackjack page at VegasSlotsOnline and try our freeplay game. Start off by keeping a running count of the cards as they are dealt. Adjust your free bets and see if you can get an edge over the casino.

Alternatively, you can practice for as long as you need right here on this page with our blackjack counter. This blackjack trainer is your go-to tool to really getting to grips with counting cards. You can also play it for free, directly via your web browser.

Card Counting FAQs

Want to learn how to count cards in blackjack? Just follow the basic rules in our card counting guide. Learn the basics of the running count and true count and master a strategy like the Hi-Lo or Omega II. You can also use the blackjack trainer we have on this page to practice online.

Good card counting can increase your edge over the casino. In fact, a good counting system can decrease the casino’s house edge by 0.5-1%. Check out our detailed guide to blackjack odds at VegasSlotsOnline.

Blackjack card counting is still used in land-based casinos where games feature multiple decks and a shoe. Casino staff can still spot a card counter and will ban anyone suspected of doing it. You will still need to learn the basics of blackjack to get a full understanding of how card counting works.

It’s easy to keep a running count and calculate the true count. However, counting gets more complex when you use an advanced multi-level system that awards a range of values to cards. Card counting becomes easier the more you practice. We recommend using the blackjack trainer we have on this page to try out the different strategies we’ve outlined in this guide.

There are lots of tell-tale signs that you’re a card counter. You are serious about winning, don’t talk during hands, and make unusual moves like splitting tens. Good card counters will also be long-term winners, alerting the attention of the casino staff.

The simplest system to use in card counting is the Hi-Lo. You add +1 to the running count for every 2, 3, 4, 5 or 6 that is dealt. You subtract 1 from the count for every 10, J, Q, K, or A that is dealt. Once the shoe has run out of cards, you start the count again.

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