Hi-Lo card counting
Card counting is a blackjack strategy: you keep track of the cards that have been played to know whether the cards still in the shoe favour you or the casino. The best known method is Hi-Lo. Every card that leaves the shoe counts +1, 0 or −1, and the sum, divided by the decks still in the shoe, tells you when to bet more. Count every card that leaves the shoe: +1 for 2 to 6, 0 for 7 to 9 and −1 for tens, court cards and aces. The running count divided by the decks still in the shoe is the true count. When it is high, the cards left are rich in tens and aces, the player has the edge, and a counter bets more. Keep the count yourself in Practice, count down a deck, or deal a million rounds and watch the edge rise with the true count.
How it works
- Watch the cards come out of the shoe: 2 to 6 count +1, 7 to 9 count 0, and tens, court cards and aces count −1.
- Read the running count on the left and the true count on the right: the running count divided by the decks left.
- Keep the count yourself in Practice, count down a deck, or deal a million rounds and watch the edge rise with the true count.
How Hi-Lo counts
Every card gets a value. Low cards, 2 to 6, count +1: when they leave the shoe, the cards that remain are richer in tens and aces, which is good for the player. Neutral cards, 7, 8 and 9, count 0. High cards, 10, jack, queen, king and ace, count −1: when they leave, the chance of a blackjack or a strong starting hand drops. A deck has 20 low and 20 high cards, so it adds up to exactly 0: Hi-Lo is a balanced count.
Running count and true count
Start at 0 when the dealer shuffles and add up the value of every card you see: that is the running count. A running count of +6 means more with one deck left than with five, so divide it by the decks still in the shoe: true count = running count ÷ decks left. Counters estimate the decks from the discard tray; the app draws the tray and the shoe with a tick for every deck.
Why a high count helps the player
Tens and aces make blackjacks, which pay the player 3 to 2, and they make the dealer bust more often, because the dealer must draw to 17. Doubling down also wins more often when tens are left. As a rule of thumb, every point of true count adds about 0.5% to the player's edge. With six decks a flat bettor starts at about −0.4%, so from a true count of about +1 the player has the edge.
Bet more, or not at all
Counting only pays when the bet follows the count: the minimum, or nothing, when it is low, and more when it is high. The app settles every round twice on the same cards: with a flat bet of 1 unit, and with a bet of 1 to 12 units chosen by the true count. With six decks shuffled at 75%, the flat bet loses about 0.4% of the money bet and the counter wins about 1%. Shuffled halfway, as in many live casinos, most of that edge disappears, and online games that shuffle after every round cannot be counted at all.
Frequently asked questions
Is card counting illegal?
No. Counting cards with your own head is not illegal. A casino is private property, though, and may refuse you as a player or ask you to stop if it suspects that you are counting cards.
Can you count cards in online blackjack?
Not in regular online blackjack: the software shuffles the cards digitally after every hand, so the count is back to 0 before every bet. At live casino tables with a real dealer on video it is sometimes possible, but they often shuffle when half the shoe is left, which leaves little edge. Try the Online and Live casino presets.
What is the true count?
The running count divided by the number of decks still in the shoe. A running count of +6 with three decks left is a true count of +2. The true count, not the running count, tells you how big your edge is and how much to bet.
How big is the edge from counting?
Small: about 0.5% per point of true count with basic strategy. With six decks, a cut card at 75% and bets of 1 to 12 units, the app's counter wins about 1% of the money bet, while a flat bettor loses about 0.4%. The swings are large, so it takes tens of thousands of rounds before the difference shows.
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