Counting Cards in Online Blackjack; Can it Be Done?

Blackjack is a casino favourite both online and off. And for good reason.

It’s fast, the rules are simple. And if you play strategically and ignore the side bets, you can whittle the house edge down to nearly nothing.

And then there’s card counting.

What is card counting?

Despite common belief, it is not a form of cheating and is not illegal.

Card counting in Blackjack is based on statistical evidence that high cards benefit the player, and low cards benefit the dealer.

The card counter attempts to keep track of the percentage of high and low cards that have been dealt. By doing so, they can then estimate when the deck has a greater concentration of high cards and increase their bets accordingly.

Unlike what you may have seen in the movies, card counting does not allow you to accurately predict what the next card will be. It merely gives you an indication of when the odds might be slightly more in your favour.

Studies have shown that, under the right circumstances, card counting can give the player an advantage in single hands. But that advantage is not enough to guarantee that you’ll break even over extended periods of play, let alone make money.

Blackjack, the card counters favourite game

Another complicating factor is that, while counting cards isn’t illegal, it is against the rules of practically all brick-and-mortar casinos.

This means gamblers who are trying to count cards must do it mentally, all the while trying to act like your average joe flirting with Lady Luck.

Which would make you think that online casinos could provide the perfect opportunity for counting cards. You can sit at home, making notes to simplify the process.

And there is no way the casino can catch you, so you don’t have to worry about being barred from the game. But is it that simple?

Is it possible to count cards in online blackjack?

Considering the points above, counting cards online should be a lot simpler than doing it offline, right?

Unfortunately, it’s not, it is actually much more difficult. In fact, most experts would agree that it is nearly impossible. Or at least, too difficult to be worth doing.

Why is this? It all comes down to one simple thing, deck penetration.

What is Deck Penetration?

If you’ve played blackjack in a bricks-and-mortar establishment, or a live dealer casino online, you’ll know that the dealer shuffles the cards before getting to the end of the pack.

The term deck penetration refers to the percentage that has been dealt before the pack is reshuffled. For example, in a 5-deck game (260 cards) where 120 cards have been dealt, deck penetration is 46%. The dealer has dealt out 46% of the cards.

This is very important to card counters who need high penetration (over 50% at least) to stand any chance of making money. A higher penetration means that more cards have been dealt and counted.

This allows the counter to more accurately predict what is left in the pack. And that, after all, is what card counting is all about.

A high-value hand, card counting online or off will not guarantee you one

Image source: Images Money

Deck Penetration in Online Blackjack

In bricks-and-mortar casinos, deck penetration regularly reaches 60% or higher, which is when the card counter makes his move. Online it is a completely different story

In online games, the deck is automatically shuffled after every hand. Practically, this means you are starting a new game with every deal. Deck penetration will never reach even 2%, let alone 60%+.

Live dealer games can offer better opportunities for the card counter. But only if the dealer is not using an automatic shuffling machine.

Even if the dealer is dealing from a shoe, they will generally reshuffle after about half the deck has been dealt, meaning deck penetration of only 50-something %.

This slows down the rate of play compared to brick-and-mortar casinos. But online casinos have much lower overheads, so they can accept a slower rate of play.


It is impossible to count cards when you are playing purely online blackjack. And even if you find a live dealer game using a shoe, the low rate of deck penetration, plus the slow rate of play means it will take you hours of play and a very big bankroll for a very low theoretical return on investment.

Like most gambling strategies (ex. Martingale System) , card counting sounds great in theory. But in practice actually means a lot of work for little to no advantage, especially online.

You’ll have a much better time if you just play and enjoy the game. Just remember to gamble responsibly and never bet money that you can’t afford to lose.