Guide

How to count cards with Hi-Lo.

Card counting is not about memorizing every card. It is keeping one running number that tells you whether the cards left in the shoe favour you or the dealer. Hi-Lo is the simplest widely used way to do it. Here are the steps.

Why counting works

Blackjack has a memory. Once a card is dealt, it is out of the shoe until the next shuffle. If a lot of low cards (2 to 6) have come out, the shoe is left with more tens and aces. That helps you, because you get more blackjacks, doubling works better and the dealer busts more. If lots of tens and aces have gone, the shoe is poorer for you. Counting is a quick way to track which of the two is happening.

Step 1: learn the three values

  • 2, 3, 4, 5, 6: +1. These are good for the dealer, so each one leaving the shoe is good for you.
  • 7, 8, 9: 0. Ignore them.
  • 10, J, Q, K, A: -1. These are good for you, so each one leaving is bad for you.

There are 20 cards at +1, 20 at -1 and 12 at 0 in each deck, so a whole deck always adds up to zero.

Step 2: keep the running count

Start at zero after each shuffle. Every card you see, including the dealer's cards and the other players' cards, adds its value. If the first five cards are K, 5, 9, 3, 2, the count goes -1, 0, 0, +1, +2. The total so far is the running count. Speed comes from pairs: a low and a high card cancel to zero, so you can skip them and only react to the extra ones.

Step 3: convert it to a true count

A running count of +6 is a lot with one deck left and not much with five. To compare, divide the running count by the number of decks still in the shoe. That is the true count. A running count of +6 with 3 decks left is a true count of +2. Counters estimate the decks left by eye from the discard tray, to the nearest half deck. The true count calculator does the division for you while you learn.

Step 4: bet more when the count is high

Each point of true count is worth roughly half a percent to the player. A simple bet ramp, in units of the table minimum:

True countBet
+1 or lower1 unit
+22 units
+34 units
+46 units
+5 or higher8 units

Real counters size the ramp to their bankroll so that a bad run does not wipe them out. Play-money practice has no such limit, which is why it is a good place to learn.

Step 5: change a few plays

At some counts the best move changes. These are called index plays. The best known: stand on 16 against a 10 when the true count is 0 or higher, stand on 15 against a 10 at +4 or higher, and take insurance at +3 or higher. Learn them last. A good bet ramp is worth more than all of the index plays together, and you must know basic strategy first, because the index plays only change it.

How to practice

  1. Count down a single deck in the counting trainer. Aim to end on zero in under 30 seconds.
  2. Add the true count with the true count calculator.
  3. Turn the count on in a coached game and track it as you play.
  4. Try the index drill when you are ready for the plays.

Counting is legal, but casinos do not welcome it, and they can end your game if they think you are doing it. This site teaches it for understanding the game and for fun. See the counting lessons for the same ideas with visuals.

Reading is a start. Cards on a table stick better.Open the counting trainer

Questions people ask

Is card counting illegal?
No. Counting cards in your head is legal. Casinos are private businesses, though, and can limit your bets, ask you to stop playing blackjack or ask you to leave if they think you are counting. Using a device to help you count is a different matter and is banned in many places.
What is Hi-Lo?
The most widely taught counting system. Cards 2 to 6 count +1, cards 7 to 9 count 0, and tens and aces count -1. You add them up as the cards come out.
Why does counting work?
Cards that have been dealt do not come back until the shuffle. When many low cards have gone, the cards left are rich in tens and aces, which means more blackjacks, better doubles and more dealer busts. That favours the player.
How much does counting give you?
Each point of true count is worth roughly half a percent to the player. With good rules the house edge is about 0.43%, so the edge turns in your favour at about a true count of +1.
Can I count cards online?
Not in games that shuffle every round, which is most online blackjack. Counting needs a shoe dealt deep before the shuffle.
How do I check my practice?
A full deck always counts back to zero, because it has 20 low cards (+1) and 20 high cards (-1). If you finish a deck on any other number, you made a mistake.

More blackjack guides

How to play blackjackCard values, what the dealer does, every move you can make, how each result pays, and one round from start to finish.Basic strategy explainedThe best move for every hand, in plain words: why the dealer's card decides it, and the rules of thumb for hard hands, soft hands and pairs.3:2 vs 6:5 and the house edgeWhich table rules cost you the most, with the house edge for each, and how to read the sign before you sit.The lessonsShort lessons with one visual each, from the basics to card counting.Free toolsStrategy chart, house edge, dealer odds and a counting trainer.

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