# How to Count Cards in Blackjack

Jan 2, 2023

As part of our blackjack strategy section, this page looks at card counting. Although card counting is best classified as being a ‘system’, it is unique in that it shapes your play, but doesn’t simply tell you to bet in a specific, systematic way. To have a look at other systematic approaches to blackjack, read our blackjack systems page.

Card counting in blackjack is the act of keeping track of what cards come out of the deck, so that you may have an idea of what remains. This is done because of the simple fact that when there is an excess of 9s, 10s, and Aces, the player is at an advantage. The opposite is true if there is a shortage of these cards. Card counting is a simple method for determining if there is a shortage or an excess of these cards.

You can take advantage of this knowledge by simply online betting big when you know you have an advantage, and betting smaller when you know you don’t. But how do you actually do the counting? Is it a skill reserved for mathematicians? Hardly, all you need to be able to do is count to one.

For every card that comes out of the shoe (not just ones dealt to your hand) you have to assign a point number of either negative 1, zero, or positive 1.

For low cards (2 thru 6) assign a value of 1
For mid-range cards (7, 8, 9) assign a value of 0
For high cards (10 thru Ace) assign a value of -1

Starting from zero, for every card dealt from the deck you’ll either add 1 to your count, add nothing, or subtract one. Your ‘running count will start from zero and then fluctuate a good deal as the cards are dealt.

Say the string of cards that came out was 3, 8, Ace, 10, 3, 9, 4 – let’s see what the running count would be after each card, starting from zero.

1, 1, 0, -1, 0, 0, 1

At the end of that short run, our running count is 1. This is all there is to card counting.

Of course, knowing that running count number is useless unless you can also make some money off of it. As we mentioned earlier, the whole point of card counting in blackjack is to know when you have a general advantage or disadvantage so that you can know whether to bet big or bet small.

So what should the count be to bet big? The larger the count the bigger you should bet. If your count is 1 or less, just bet normally. If the count grows to 3 or more be sure to increase your bet a little. If it climbs up to 8 or more, bet big.

There is one complication we haven’t mentioned yet. The above system is designed for a one-deck game of blackjack. We all know one-deck games are few and far between, and multiple-deck games have become standard fair at casinos. Adapt this card-counting technique to multiple decks is quite simple. You need to look and take a fairly good guess at how many decks appear to be left in the shoe. If you are playing a six-deck game and approximately two decks worth of cards have been played, there will be about twice as much left in the shoe as there is in the dead cards pile.

To calculate a ‘true count’ for your multiple-deck game, count as you normally would, but take this running count and divide it by the number of decks remaining in the shoe. The resulting number can be treated as the normal count from a single-deck game (meaning, when it’s big, increase your bet).

This card-counting system is one of the simplest methods available for counting. The simplicity of course makes the results a little less precise than more complicated systems, but overall it is a very good way to learn to count, as the concepts are shared between systems.