Counting Cards in Blackjack - Legality, Benefits and Challenges

Blackjack Card Counting - Is It Illegal?

Counting cards is a strategy a number of players swear by in order to improve the house edge in Blackjack, as well as other card games. You might have seen this being done in movies, which has caused you to wonder if card counting really works and how it is done. Our experts have taken a closer look at the possibilities, as well as the legality of card counting, which you can read all about below.

Is Counting Cards in Blackjack Really Illegal in the UK?

Many players out there believe that card counting is illegal. However, this is not the case. There are some grey areas that are worth knowing about, whether you decide to play at online or physical casinos.

Casinos are far from fond of players counting cards and will do everything in their power to prevent card counting. A number of casinos even view it as cheating and do, in fact, have the authority to ban anyone they suspect of using this method. If you are caught counting cards, both online and physical casinos will have the right to refuse you ever playing at their establishment again.

This is simply because the casinos know very well that professional card counters will have a clear advantage over the blackjack house, and no casino enjoys losing money. To avoid this and catch card counters, they often use surveillance, and dealers might even be encouraged to start a conversation to distract the player.

It’s also worth noting that while card counting is not illegal, the use of any devices might be. This could be equipment such as small cameras or specific programs, and if you are caught card counting using devices like this, you might also risk criminal charges.

What is Card Counting in Blackjack?

When using any card counting system, the idea would generally be to keep an eye on the high and low cards throughout the deck. By doing this, you will be able to conclude if the number of cards left in the deck is better for you or not. This results in gaining an advantage over the house.

In order to count cards, what you are doing is keeping track of which cards already have been in the game based on the cards that have already been revealed. This is the case no matter if the game of blackjack is online or not.

The running count will be your total based on the cards that have already been dealt. If the count is negative, the house will have the edge, and when it is positive, you, as the counter, will have the edge. Seeing that many casinos use several decks in the game, it is wise to establish a true count.

The way this works is that if you have a running count of +4 at the end of the first round in a game with four decks, then your running count will be +1. Should you have the same running count of +4 when there are just two decks remaining, then the running count will be +2.

The formula that can be used here is as follows:

  • Running Count ÷ Decks Remaining

How Counting Cards in Your Head Can Give You an Edge

How Counting Cards in Your Head Can Give You an Edge

By learning how to count cards and using it as a basic Blackjack strategy, you will be able to slightly increase your odds of winning. If you do it right and learn the right ways, you will be able to go forward in playing a simple buy strategic game.

Card counting is seen as an effective way of increasing the chances of winning, but of course, as any strategy, it is not a guarantee. As you keep track of the cards that have already been played, you will be able to adjust your bets and strategy throughout the game. This will allow you to take advantage of the cards that remain in the deck.

Higher probability of a dealer going over bust

In a game of Blackjack, the dealer has to hit on a soft 17, the same goes for if the dealer has a soft 16. Should this happen while the deck has many high cards, it will considerably increase the chances of the dealer going bust.

The player at the table will never be required to hit on a specific value during the game, which means you will be free to play as you wish should the deck of cards hold a large amount of high cards.

Enhances Your Odds of Hitting a Blackjack

During the game, there will be a higher chance of you scoring a Blackjack if there is a higher amount of tens and aces. This, however, also goes for the live dealer at the Blackjack table. Although, seeing Blackjack pays 3 to 2 in favour of you as the player, this will remain a hand of higher value for players rather than the dealer.

Increases Your Chances for a Profitable Double Down

Should your card counting reveal that there is a higher proportion of cards left in the deck, going for a blackjack double down will be far more favourable. This is due to the fact that there is a larger chance of drawing a card that leaves you with a strong hand. By having the knowledge that there are higher cards in the remaining deck, you will have a better chance for a profitable double down.

Optimizes Split Decisions for Card Counters

One of many reasons why card counting often is profitable for players is that player splits are more successful. This is seen in card decks that have a higher amount of tens and aces remaining in them. Such a deck will often result in more successful split hands seeing that they are stronger hands when compared to a weak dealer card. In cases like this, the dealer of the game will tend to bust when the player splits.

More Frequent Insurance Payouts to the Player

When you’re counting cards in a game, you will see that insurance pays off more often in Blackjack. This is true when a deck has a larger amount of tens and aces, which will automatically make it more likely to get a Blackjack on your hands. In these cases, insurance will be a great bet for you as a player.

Practising Card Counting for Blackjack

We have created a simple step-by-step guide below on how card counting works:

  1. Assign cards a value of 0 (for cards 7 to 9), +1 (for cards 2 to 6) or -1 (for cards 10 to Ace).
  2. As the blackjack dealer pulls a card in the deck, keep track of every single card while using the values above.
  3. If you have managed to keep track correctly of the cards dealt, you will be able to keep track of the value of the cards remaining in the deck.
  4. Increase the size of your bet after every round if the count is negative. This means that there will be a larger amount of low-value cards left in the deck.
  5. Lower the size of your bet after every round if the count is positive. This means that there will be a larger amount of high-value cards left in the deck.

Learning the values for the count will require some practice, especially if the dealer is working fast. Once you have learned the values, you will be ready to start counting cards. In order to get the most out of your card counting, you should also be applying a basic strategy while focusing on keeping count. As any other game, practice makes perfect

When seeing that the count is high, make sure you are keeping the true count in mind. At this point you will be able to increase your bet and slightly change your strategy.

Challenges of Card Counting in Online Casinos

Challenges of Card Counting in Online Casinos

Card counting can result in a higher chance of winning in a game, as the method relies on the thought that some cards are more favourable to you while others are better for the dealer. Card counting at an online casino is, however, much harder than using the technique at a land-based casino.

The reason for this is that online casinos are able to use the very latest technology, making it nearly impossible to count cards. For virtual games, the casino will use RNG, which is a Random Number Generator, in order to make sure everything is fair and controlled by a computer. In terms of live blackjack games, there will be several decks in play, in addition to shuffles taking place more frequently.

Ever wondered how casinos manage to outsmart card counters?

As we have touched on briefly above, card counting in an online casino is simply not possible due to the use of the latest software. When playing Blackjack online, you will have to make use of other strategies or tactics in order to give yourself a better chance of winning.

There is, however, one small exception to the rules, which is live blackjack. As these games will use a live dealer, streamed directly to players’ screens, you might be able to count cards in order to gain that edge over the house.

Can you tell if someone else is counting cards?

There are several ways to tell if someone is counting cards in a game; however, recognizing card counting requires extensive knowledge and experience. Some casinos even hire ex-counters to help them identify those suspected of counting cards.

Some of the signs you can look for include:

  • Players increase their bet amount when low-value cards are dealt
  • Players who bet more at the latter part of the shoe
  • Players who show a lack of consistency
  • Players using blackjack insurance

Can a casino boot you out just for being too good at maths and memory?

The answer to this is that while card counting isn’t illegal, casinos have the right to kick you out and even ban counters. This goes for both land based casinos, as well as online options. What makes it illegal, however, is using an external card-counting device, which you should avoid doing unless your goal is to be banned from several casinos.

Counting Cards is 100% Legal in Vegas, Too

The laws surrounding counting cards differ between countries and even between states in the US. Contrary to what many believe, card counting is legal in the United States. There are no federal, state, or local laws stating that it is illegal. The only exception here is for players who choose to use an external counting device.

However, seeing that land-based casinos are private establishments, casinos reserve the right to kick them out without any reason. It might also be worth noting that casinos in Vegas and other large cities share information, which can cause casinos to catch serial counters.

The same goes for playing Blackjack in the UK, where counting cards is not illegal either. It is, however, frowned upon by casinos, and counting cards might have you banned from playing.

Blackjack Card Counters in Hollywood

Card counting is something that has been almost glamorised for many years thanks to Hollywood movies. There have been a number of iconic films where card counters with huge success, landing big wins and beating the dealer have been shown. For some reason, movies have always shown card counters to be the winners, and maybe this is exactly where the hype surrounding card counting comes from.

Card counting has been portrayed as an unbeatable system that almost guarantees wins every single time. However, the reality is, of course, quite different. In many cases, it might even be a waste of time as it is difficult to learn and even more so to master. So, while this technique can offer a slight advantage over the casino, a basic strategy will usually work just as well.

King’s Verdict: Is Card Counting Worth the Effort?

There are both advantages and disadvantages to card counting. Starting with the obvious, counting cards will allow you to significantly lower the house edge, which in return will increase your chances of winning.

Even so, it is wise to keep the risks in mind. When it comes to card counting in both land-based casinos and online casinos, the biggest risk is getting caught. This could result in being banned from casinos for a certain amount of time, or even for life. Of course, another disadvantage is that there is no real guarantee of winning in the short term, so in the end, it is up to each player to decide if the risks are worth it or not.


  • Lowers the house edge
  • Increases your chances of winning


  • Might result in being banned
  • Illegal when using a card-counting device

If you are looking for alternatives to increase your chances of winning without having to be among the successful card counters, there are several betting and playing strategies to choose from.

By using the right strategy, you will be able to lower the house edge, and playing with a basic strategy will allow you to reduce the house edge to 0.5%. The most common option is making yourself familiar with a basic strategy chart, while also using a blackjack casino bonus for extra funds. A great way to start is LeoVegas Casino’s live dealer promo, which will allow you to become accustomed to the strategy. This will, in turn, allow you to know the correct move for each situation during the game as it is based on the cards you have been dealt, as well as the dealer’s upturned card.

These are some of the main key points from a basic strategy:

  • Stand on 17+
  • Never Split 10s
  • Double Down on 11
  • Split 8s and Aces

Selecting the correct Blackjack game for you is also part of a great strategy, as even the smallest variations could make a game considerably more favourable to the house. If you need some ideas on where to get started, have a look at some of our favourite Blackjack casinos. Look for some of these rules when selecting a game:

  • Single Deck – Fewer decks in a game will give the house less advantage.
  • Surrender – Allows players to forfeit a hand while only losing half of their bet.
  • Double Down – Double the stake for a single additional card.