(How) Does Counting Cards Work?

We don’t condone cheating, nor do we think that playing blackjack is a good way to do business. This is why we are approaching this problem strictly from the theoretical perspective. Some people swear by it and casinos might blacklist you if they figure out you use it but does card counting actually work? And, if so, how? For the purposes of this article, we will consider blackjack as our game.


As it turns out, there are several systems for card counting that people use now and again. The most popular strategy is Hi-Lo, which divides cards into three categories: low cards (worth one point) middle cards (worth zero points), and high cards (negative one point).

It boils down to this – the better the running count, the better the chance of winning. Let us explain: you don’t look at your cards alone. For this to work, you need to consider the dealer’s cards, as well as those of other players. Tally the score and if it’s positive, you have a chance to win.

True Count

Another factor that needs to be considered is the number of decks. If you have a single deck, then the Hi-Lo system is effective. If there are several decks, some adjustments may be in order. Divide the running count with the number of decks and you will get another number that gives you a more accurate representation of your fighting chances.

Does It Work?

Now, for the big reveal – yes, but only to a degree. A team from MIT managed to make a killing by betting on blackjack, but that’s MIT we are talking about, so the calculations were probably more complex than simple card counting systems. Additionally, they played as a team, which improved their chances of winning significantly.

The truth is that card counting increases the odds of you winning, but does not guarantee it. Remember, players have limited funds, unlike casinos, which means that they don’t stand a chance in the long run.

Even if you do manage to find a card counting system that works best for you, it isn’t a magic spell – anything done can upset the calculations: new decks, a different number of players, or a plethora of other factors could put a wrench in your plans.

Going Online

When people play online, they have no idea how many decks are in play, which immediately ruins the plans. Furthermore, while human dealers shuffle cards, online shuffling operates on an RNG, or random number generator. You are welcome to try and use the systems, but don’t expect much.


The gist of it is this: counting cards can give players an edge, but does not guarantee a win. There are dozens of card counting systems and they all require a lot of focus, taking the fun out of the game. Card counting systems become even more intricate for more complex games. Does it work? Sort of. Is it worth it? Not really.


Naturally, regardless of whether card counting works or not, it is more than frowned upon. You will not go to jail, but you will be asked to leave if your technique is discovered. Furthermore, if you enjoy gaming, it could be very unpleasant to get banned from playing in casinos. Food for thought.