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Card counting in online blackjack

Card counting is the best-known method of tipping casino odds in your favour – it’s not technically cheating, although it is still banned in many land-based casinos.

It doesn’t necessarily involve memorising every card that is dealt – instead, several different systems can give you an idea of when you are most likely to win (scroll to the end of this guide for some of the main methods used).

The practice first gained widespread attention in the film Rain Man, a 1988 movie starring Tom Cruise as Charlie Babbitt and Dustin Hoffman as his autistic brother Raymond. A major part of the plot of the movie concerns Charlie and Raymond ‘cheating’ at blackjack, thanks to Raymond’s savant-like ability to remember which cards have already been dealt. Card counting has also made appearances in the plots of other blackjack-themed films, including 2008’s star-studded ensemble piece 21.

Card Counting in Online Casinos

If counting cards in land-based casinos is banned, then you might be tempted to try it in an online casino, where it is harder for the dealer or operator to keep a close eye on your actions. However, you are likely to be wasting your efforts, as online blackjack is usually based on a random number generator.

As such, there is no concept of counting ‘cards’, as each new hand is generated at random; if you are dealt an Ace-King blackjack in one hand, you could be dealt the exact same hand, of the same suits, in the very next hand. Of course, statistical probability means it is unlikely that this will happen, but unlike when a deck is used in full before being shuffled, it is no more likely that the hand will not be dealt again, simply because it has been dealt once.

So, is card counting completely irrelevant in online blackjack? Not necessarily…

Card Counting in Live Casinos

Where a casino has a live dealer, it may still be possible to count cards, as here it is more likely that multiple hands will be dealt from a real deck, before it is reshuffled.

This means, unlike with random number generator (or ‘RNG’) blackjack, card counting can theoretically improve your odds of a win – or, at least, give you an idea of when it is worth betting larger amounts based on the cards you are dealt.

But although your chances of successfully counting cards are much higher in live dealer games, there are several reasons why it is still probably not worth the effort:

  • Deck penetration is the term given to the proportion of the deck that must be dealt through, before the deck is reshuffled. Usually expressed as a percentage, it means there will always be a certain number of cards left when the deck is reshuffled, removing the possibility of ever predicting the deal with 100% accuracy by card counting.
  • Burn cards compound the problem, as this sees several cards removed from the top of the deck, face down, immediately after it is reshuffled. An additional card is typically ‘burned’ between hands – and as you never see these cards face up, it’s impossible to incorporate them into your count.
  • Slow play rates can mean, even with deck penetration as low as 50%, it can still take an awfully long time before you have counted a meaningful number of cards. This can make it easy to keep track of the count, but means you could be left waiting a long time before you get a hand worth betting big on.
  • Player numbers can worsen the odds even further, as you face the excruciating possibility of watching a player in a neighbouring seat receive a favourable hand deep into the deck, while you receive a hard hand in the mid-teens.

With all of this in mind, the statistical advantage you gain through card counting is eroded substantially, until it becomes barely worth the effort. If you still feel compelled to count cards, you’ll need to be prepared to gamble big on any choice hands that come your way – and still be open to the possibility of losing your wager.

Card Counting Background

There are several possible methods of counting cards that are in common usage:

Hi-Lo Systems

Hi-Lo systems are based on the principle that a deck containing more high-value cards is good for the player, while a deck of low-value cards is better for the dealer. Each time a high card is dealt – a Ten or above, for instance – you subtract 1 from the running total in your mind. For every low card – a Six or below – you add 1. If the overall count goes negative, you stick to the table’s minimum wagers; if it goes very high, +8 or above, it is theoretically a good time to bet bigger.

Multilevel Systems

A multilevel system is similar to the basic high-low system described above, but with some cards assigned a +2 or -2 rating – usually +2 for Fours, Fives and sometimes Sixes, and -2 for Tens to Kings. These are harder to keep track of, as your running count can change by a greater degree when a single card is dealt, but can also give you a better idea of how much you should bet.

Separate Ace Counts

If your short-term memory is up to the task, you can maintain a separate or ‘side’ count of how many Aces have been dealt. This can help to bring the fairly basic strategy of your card counting in line with more complex blackjack systems that govern not just the bet, but also when to hit or stand.

Again, there is a compromise to be struck between the complexity of the system, and the likelihood of winning; in some cases, a more basic system with a smaller win percentage can lead to larger overall winnings, as it allows you to play more hands more quickly. But in online blackjack – particularly RNG blackjack – it is unlikely that any system will lead to a significant increase in earnings.