How to Count Cards in Blackjack

Posted by Chris Spencer . Last updated:

Counting cards is an in depth discussion and can’t be covered on a single page, but when you learn how to count cards in blackjack, you can gain an edge against the casino. Because blackjacks pay more than even money and you have the opportunity to double and split in favorable situations, if you can change the bet size based on the remaining cards in the single or multiple decks you can shift the house edge to your advantage when you play blackjack and other casino card games.

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How to Count Cards in Blackjack

Almost anyone can learn to count cards. I won’t tell you it’s easy, but it’s probably not as hard as you think. Statistically, if more high cards remain in a deck than low cards, the edge moves toward the player. When the high cards have been played at a higher rate than low cards the edge is shifting toward the house. From the top of the deck or shoe, the house edge is strong.

Basic strategy counting systems only require the ability to add or subtract one at a time and keep the total in your head.

Here’s an example. If you start at zero (where many counts start) and the following hands are played, you end up with a count of +1 using the popular Hi Lo system.

When you learn how to count cards in blackjack, you can gain an edge against the casino.

  • Hand 1: 2 – 5 – 6 – 6
  • Hand 2: ace – ten
  • Hand 3: king – queen
  • Dealer: ten – 4 – 3

In Hi Lo, all cards 6 and below are +1 and all cards 10 and higher (including aces) are -1. You see six +1 cards and 5 -1 cards, so the new count is +1.

If you can do that, you can learn how to count cards.

Difficulties of Counts – Level System

Card counting systems are generally put into groups depending on their supposed difficulty.

Some counts are harder than others, and if you can’t keep an accurate count you’ll lose the edge counting is supposed to give you.

You’re always better off playing a less effective system perfectly than a more advanced system with mistakes. Pick an effective system and master it. Don’t worry about finding the most powerful system known to man.

Each of the system summaries below includes a level. The level is simply the highest number you need to add or subtract from the count. A system that only adds or subtracts one is a level 1 system and a system that adds or subtracts two is a level 2 etc.

How to Count Cards in Blackjack: Playing Strategy

Running vs True Count

The running count is the count you keep in your head as the cards are played. It goes up and down as you play blackjack through the shoe.

In a balanced system (covered in the next section) you have to divide the running count by how many decks are left in the shoe. The closer you can estimate the number of remaining cards and, moreover, remaining decks the better your , will be. Most professionals recommend being able to determine to the closest quarter of a deck how many cards are left.

The reason you have to divide the running count by number of decks left to play is to get a “true” idea of the advantage per deck.

In an 8-deck game, if your count is +2 after the first hand has been dealt, the casino still has an advantage because such a small percentage of cards have been dealt.

Balanced vs Unbalanced

A balanced count ends at zero if you count an entire deck of cards and an unbalanced count ends with a positive or negative number after counting an entire deck. (Unbalanced counts usually end with a positive number.)

The advantage of an unbalanced count is you don’t have to convert your running count to a true count. While this may seem like a huge advantage, the truth is most players who can learn to count don’t have any trouble converting counts on the fly so it isn’t a big deal.

Unbalanced counts generally don’t start at zero. The starting number will depend on how many decks are in play.

Here’s an example. In a single deck game the count might start at -2 (minus two) and in multiple decks games it might start at -12 (minus twelve).

Balanced counts usually start at zero, but any count can be modified to the user’s needs.

Here’s an example. If you don’t like working with negative numbers you can start counting at 10 instead of zero. When your index plays call for a certain play at +4 and above, you know to use it at +14 and above.

One of the most popular unbalanced counts is the Red 7.

Side Counts

A side count is an extra count you need to keep while also maintaining your normal count.

If you think it sounds complicated, you’re right.

The most common side count is keeping track of the aces as they’re played. Some counting systems don’t account for aces in the regular count and track them on the side.

Omega II System

The Omega II system listed below uses an ace side count.


Playing Strategy

Hi Low or Hi Low

The Hi Lo is the most popular system. It’s a balanced level 1 system.

Ace Five

By far the easiest count, it only tracks two cards. It’s a balanced level one system. Because of the simplicity of the system, it’s also the least accurate on this list.

Red 7

An unbalanced level 1 system, you also have to be aware of the color of sevens as they’re played. This adds a small level of complication to the system, but not having to convert to a true count makes up for it.

10 count

The 10 count was the system listed in the famous book by Thorp, Beat the Dealer. It’s not used any more, but it’s the basis for every other system on this page. It was designed for the single deck game and used +4 and -9.

Revere Advanced Plus Minus

A level 1 balanced count.

Wrong Halves

Famous gambling author Stanford Wong’s system is a balanced system and is unique in using halves (.5) in the count. It’s usually listed as a level 3 system because it uses .5, 1, and 1.5.

Revere Point

The Revere Point count is a balanced level 2 system.

Unbalanced Zen II

A level 2 unbalanced counting system.

Hi Opt 1

The Hi Opt 1 is a level 1 balanced system.


Another popular system, the KO (or K-O) is an unbalanced level one system.


The REKO is a variation of the KO. It’s a level 1 unbalanced system.

Uston Advanced Count

A level 1 balanced count.


The Zen count is a level 2 balanced system.

Counting Cards Online Vs. A Land-Based Casino

There are pros and cons to everything in life and playing online blackjack is no different. When it comes to counting cards, though it’s not illegal at the federal or state level, it is frowned upon by pit bosses at brick-n-mortar casinos. So, when you do it online, you don’t have to worry about those guys peering over your shoulder or consider the “eyes in the sky” tracking your strategy. It’s a more peaceful and less stressful experience.

How to Count Cards in Blackjack: Conclusion

Counting cards is one of the best ways to give yourself a real chance to beat casino games. Take a few minutes to look through the systems to find one that looks like it’ll work for you.

I know I listed a bunch of them, but don’t get overwhelmed. If you master any system it will help you get an edge.

If you’re having a hard time getting started I suggest learning about the Hi Lo and Red 7 first. Both are popular systems and you’ll learn the advantages and disadvantages of balanced and unbalanced systems as you learn more about each system.

Blackjack Card Counting FAQs

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