Card Counting in Blackjack
Films such as 21 and The Last Casino have introduced many viewers to card counting. The method is most closely associated with blackjack: players track which cards have appeared to estimate whether the cards still to come may favour the player or dealer. The house usually holds a strategic advantage, but careful play can shift the odds in a player's direction. Card counting is one approach that may improve a player's chance of finishing ahead, though it cannot assure a win.
How Card Counting Works
Blackjack can be dealt from one deck or several, depending on the game. Since cards are removed from play as hands are dealt, keeping track of selected cards can help estimate what remains. Card counting means maintaining that tally while the dealer works through the shoe.
The basic counting process has these steps:
1. Assign a Value to Each Card
A photographic memory is not required to count cards. Many players use a tagging method instead: give each card a numerical value, then update a total by adding or subtracting as cards appear on the table.
Hi-Lo is a widely used, relatively simple counting system. It assigns each card a value of -1, 1, or 0; across a single deck of 52 cards, the values balance to zero. The card groups are scored as follows:
- Cards 2-6: 1
- Cards 7-9: 0
- Cards 10-Ace: -1
2. Keeping a Running Count
When a card is dealt, update the total by adding 1, subtracting 1, or leaving it unchanged according to its assigned value. Starting from zero, a queen takes the count to -1; if the next card is a 4, the count returns to 0 (-1 plus 1 = 0). A higher running count indicates that more high-value cards may remain in the deck.
3. Calculating a True Count
Casinos often deal blackjack with several decks, making a count harder to maintain but not rendering the method useless. In a multi-deck game, convert the running count to a true count, also called a count per deck, to account for the cards still in play.
Divide the running count by the estimated number of decks remaining to find the true count. For instance, a running count of 10 with 5 decks left gives a true count of 2 (10 ÷ 5).
4. Changing Your Bets Based on the True Count
As the shoe progresses, the true count may rise or fall, and some counters vary their wager accordingly. They may bet more when the count rises and keep wagers small at a neutral or negative count. Any betting decision also needs to account for the player's bankroll.
Is Card Counting Really Effective?
New players often ask whether counting cards works. The answer depends on the game and the player's skill: a capable counter can gain a modest edge over the casino, but it is not a large one. Experienced counters may achieve an advantage of about 0.5% to 1%.
At online casinos, counting is generally less useful than at a table, including a live-dealer game. Online live casinos may make tracking difficult by dealing from 8 decks, shuffling automatically, or burning cards at the start of the shoe. These measures can make an accurate count difficult or even impossible.
Consequences of Card Counting
Although card counting is not yet illegal, a casino may ban a player it believes is counting. Casinos can also alter table conditions: they might change the minimum or maximum bet, place the cut card earlier, or bring in automatic shuffling machines. Such measures reduce the usefulness and enjoyment of counting at that table. Rules and consequences depend on the jurisdiction and venue.
Getting Started with Card Counting
Learning to count cards takes steady practice and patience. It does not require exceptional intelligence, but a player does need to think quickly and do mental arithmetic. With time, practising the count may also build familiarity with blackjack decisions.
