How to count cards in blackjack
Give every card a value: 2 to 6 count +1, 7 to 9 count 0, tens and aces count −1. Add them up as cards are dealt (the running count) and divide by the decks left (the true count). A high true count means more tens and aces remain, which favours the player.
Checked 2026-11-07. Source: Hi-Lo values and worked example below.
The Hi-Lo values
| Cards | Count | Why |
|---|---|---|
| 2, 3, 4, 5, 6 | +1 | Low cards help the dealer; once they are gone, what is left is better for you |
| 7, 8, 9 | 0 | Roughly neutral |
| 10, J, Q, K, A | −1 | High cards help you: more blackjacks and more dealer busts |
A full deck has five +1 ranks and five −1 ranks of four cards each, so counting a whole shoe always ends at 0. That is a quick way to check yourself.
Running count and true count
true count = running count ÷ decks left to be dealt
Worked example, 6-deck shoe. The first cards are 10, 4, 6, 2, A, 9, 5, 3, 10, 6, 2, 8. Their values add up to a running count of +4. 300 cards (5.8 decks) are left, so the true count is +4 ÷ 5.8 = +0.7.
Practise counting
Flip cards, keep the running count in your head, then check it. Start with one card at a time and a single deck, then move to six decks.
19+ in most of Canada (18+ in Alberta, Manitoba and Quebec), 21+ in most US states. A calculator shows what a bet pays, not how likely it is to win. Free help: 1-800-GAMBLER (US), ConnexOntario 1-866-531-2600 (Ontario), 211 (Alberta). More help.
Why the count matters
Insurance is the clearest case. It pays 2 to 1, so it breaks even when exactly one third of the unseen cards are tens. A fresh 6-deck shoe has 30.8% tens, which is why basic strategy never insures; if 25 low cards have gone and no tens, the share passes one third and insurance starts to pay. The trainer tells you when that happens.
A high count also makes blackjacks, which pay 3 to 2, more likely for you, and makes the dealer, who must hit 16, bust more often. Counters bet more when the true count is high and less when it is low.
Count while you play
The blackjack simulator uses a real 6-deck shoe. Open its table rules, tick "Show the Hi-Lo count" to check yourself, then untick it and keep the count alone. Learn basic strategy first: counting only helps on top of it.
Is card counting legal?
Counting cards in your head is a skill, not cheating. Casinos still set their own rules: they can ask a player they suspect of counting to stop playing blackjack, limit bets or shuffle more often, and using a device to count is prohibited in many jurisdictions. Online blackjack that reshuffles after every hand cannot be counted, so check how a game shuffles before you try.
Questions
How do you count cards in blackjack?
Use the Hi-Lo system: add 1 for every 2, 3, 4, 5 or 6 you see, subtract 1 for every ten-value card or ace, and ignore 7, 8 and 9. Keep that running count through the shoe and divide it by the decks left to get the true count.
Is card counting illegal?
Counting in your head is not cheating, but using a device to count is banned in many places, and casinos can stop counters from playing blackjack or shuffle more often. Online games that reshuffle after every hand cannot be counted at all.
What does a high count mean?
More tens and aces are left than usual. That makes blackjacks (paid 3 to 2) and dealer busts more likely. Insurance pays 2 to 1, so it breaks even when tens are one third of the cards left; a full 6-deck shoe has 30.8%.
What is the difference between the running count and the true count?
The running count is the raw total; the true count adjusts it for the cards still to come. In our example a running count of +4 with 5.8 decks left is a true count of +0.7.