How Do Casinos Detect Card Counting?

If there’s one gambling trick or strategy that is known to really work, it’s card counting at the blackjack table. While there are hundreds of different techniques and strategies that are sold to gullible gamblers and promise to help even out the odds at every game from the slots machines (laughable) to the roulette table (highly unlikely in a proper casino with reputable equipment) to poker games (about as likely as getting a Royal Flush) to the craps shoot (a total load of …) and every game in between, most pro or at least experienced players know that luck is the only constant in a game of chance.

There are strategies that can help you BET better, to help you maximise your time and money in a casino, but no proven strategies for winning at casino games.

Except for card counting.

South African gamblers, both online casino visitors and land-based casino visitors, have seen or heard about card counting – most likely from movies such as 21. And just like you will see in these movies, card counting can nudge your game your way if you know how to do it right.

Unfortunately, casinos know that card counting can lessen the house edge and are looking for those players who can calculate the deck in their heads. And usually either ask them to leave or change the way the game is being played to negate the card counter’s advantage.

What is card counting?

Card counting is a mathematical process for working out where the advantage lies in a game of blackjack. While the process itself is a fairly simple one to understand, it can be a bit difficult to pull off if your addition and subtraction skills are not super strong.

In a nutshell, card counting allows you to work out the probable chances of high and low value cards remaining in the deck and adjust your betting strategy accordingly.

Card counting with one deck is possible for most of us but when you start adding in multiple decks it can be difficult to keep track of without a pen and paper or calculator or pulling off your shoes so you can use your fingers AND your toes to keep the count going.

We have a great article on the basics of card counting in our Guides section if you want to know more about the how’s and when’s of the blackjack player’s best friend.

Is card counting illegal in a casino?

No. Not at all. But it is heavily frowned upon by the casino. They don’t like it when players have an advantage.

And no, this is not a Vegas Mob movie, you won’t get your fingers broken but you will probably be asked to leave.

card counting

So, how can a casino detect if you’re card counting?

The obvious secret behind successful card counting is being able to do it in your head. If you start jotting down numbers on a notepad or whipping out your mobile to access the calculator app, you are going to get caught fairly quickly.

Likewise, counting under your breath will probably be a bit of a giveaway.

But even for those math geniuses (genii?) among us, the casino can pick up on who the card counters at a table are using quite simple cues.

Your bet pattern

Card counting lets you work out what the most likely value of cards to come will be. This is obviously far more evident toward the end of the shoe as there are fewer cards left to choose from.

And this is obviously where a card counter can start to make educated bets and thus bet higher in the hopes of a higher win.

Casino dealers and pit bosses know to look out for players who consistently start raising their bets as the shoe starts to dwindle.

Casino dealers and pit bosses also look for players who change their bets as more lower value cards start being eliminated from the decks. While this is not proof that a player is counting cards, it is a warning sing for the casino and will probably get the dealers attention and will probably result in your play being watched a lot more closely.

Splitting against all known advice

Every blackjack player worth their title knows that you NEVER split 10s. It’s a basic and standard part of blackjack strategy. So, when a player chooses to split 10s, especially if there’s a big bet on the table, it’s a sign to the dealer that this is possibly a card counter. The saying goes: “only dumb players and counters split 10s”.

Which kinda makes us dumb players? We always split 10s because we like to have LOTS of hands going at the same time. Not smart but, hey, we do this for fun so…

The insurance scam

Proper blackjack players know that you NEVER take insurance. It’s a ploy that invariably only benefits the casino. Seeing a seemingly experienced player take insurance is less a sign and more a slots-level ringing bells and flashing lights indication that the player is running a count.

What can the casino do to stop a card counter?

Back in the dodgy days of Sin City there were plenty of stories of card counters having their fingers pay a visit to Dr Hammer (just like that famous scene in Casino – still makes us shudder). Nowadays things are far more civilised. If you are suspected of counting cards, you will more than likely just be asked to leave the table and maybe even the casino.

And they can pick up the counters. With cameras everywhere in the casino, especially South Africa casinos, they can watch your play without you even knowing it. They can see what you are doing and how you are betting. They can even have the boss go through the discard pile and do a backward count of cards to see how your play has been going up to that point. These are very clever people, remember.

But throwing out players who are winning is never a good look for a casino, so they do have other ways of making things difficult for counters, ways that are far more subtle.

The subtle play

It may be as simple and understated as the pit boss just coming up for a lengthy – and friendly – chat to disrupt the player’s concentration and break their count.

Changing the rules

Casinos have the right to change rules as they see fit so you might see a table or player suddenly being told that they cannot double after a split, or that they cannot late surrender.

Hitting the deck

No, not dropping to the floor, rather it’s about changing how the deck is dealt. Modern casinos use card shufflers to make the game that much fairer and more random (at least fairer for the casino). But they do generally have a discard pile to the side that is only put back into the shuffler periodically.

By shuffling the cards more frequently, like after every hand, card counters have no way of being able to run the count because every hand is now random and starting from scratch.

Adding more decks to the play is also a good way of muddying the waters for counters – the more decks, the more difficult it is to run an effective count.

Beating the casino

If you do have the mental power to be an effective card counter (not us in any way, shape, or form) Then you can still put your skills to use without risk. All you need to do is vary your gameplay, make sure you are not getting into a pattern that the dealer or pit boss can pick up on, and don’t try and push your luck by winning too often or too much.

The CasinoPlay crew, as mentioned, can’t count beyond ten without taking off our shoes so we rely totally on luck. But we still know that there is only one basic strategy that will always lead to a winning (in spirit if not wallet) visit to the casino: play responsibly!


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