How to calculate the true count in blackjack
The true count tells you how good or bad the rest of the shoe is for you. You get it in two steps: keep a running count of the cards you've seen, then divide it by the number of decks still left to deal.
Step 1: the running count (Hi-Lo)
Hi-Lo is the most widely used count. Start at 0 when the shoe is shuffled and adjust for every card you see:
| Cards | Count | Why |
|---|---|---|
| 2, 3, 4, 5, 6 | +1 | Low cards leaving makes the rest of the shoe better for you |
| 7, 8, 9 | 0 | Neutral |
| 10, J, Q, K, A | −1 | High cards leaving makes the rest worse for you |
A full shoe adds up to exactly 0, so the running count always comes back to 0 if you count every card.
Step 2: divide by the decks left
True count = running count ÷ decks remaining. A running count of +12 means a lot with 2 decks left (true count +6) and much less with 6 decks left (true count +2). Dividing puts every point of the count on the same scale.
Example: on an 8-deck shoe, 208 cards (4 decks) have been dealt and your running count is +10. There are 4 decks left, so the true count is +10 ÷ 4 = +2.5.
What the true count means for your edge
A useful rule of thumb for 8-deck games: the casino starts with an edge of about 0.5% with good rules, and each point of true count moves about 0.5% towards the player.
| True count | Rough player edge |
|---|---|
| 0 or below | Casino ahead (about −0.5% or worse) |
| +1 | About even |
| +2 | About +0.5% |
| +3 | About +1% |
| +4 | About +1.5% |
These are averages from the rule of thumb, not exact figures. The real edge depends on the table's rules and on exactly which cards are left.
Strategy changes that matter most
A few plays change with the count. These are the best-known ones (from the "Illustrious 18" list) and how they're usually given for multi-deck games:
| Hand | Basic strategy | Change when the true count is |
|---|---|---|
| Insurance | Never | Take it at +3 or higher |
| 16 vs 10 | Hit | Stand at 0 or higher |
| 15 vs 10 | Hit | Stand at +4 or higher |
| 12 vs 3 | Hit | Stand at +2 or higher |
| 12 vs 2 | Hit | Stand at +3 or higher |
| 10 vs 10 | Hit | Double at +4 or higher |
Our 16 against a 10 chart shows the switch from hitting to standing happening just above a true count of 0, worked out from the exact cards left.
The hard part at live tables
Counting is simple; doing it fast is not. At an online table, cards for seven seats and the dealer appear in seconds, and you have to estimate the decks left without seeing a discard tray. Most errors come from losing track during a busy round.
Questions people ask
What is a good true count in blackjack?
In an 8-deck game, +1 is roughly break-even, +2 is about a 0.5% player edge and +3 about 1%. Below about +1 the casino is still ahead.
How do you calculate the true count?
Divide the running count by the number of decks left to deal. A running count of +10 with 4 decks left is a true count of +2.5.
What is the difference between running count and true count?
The running count is the raw total of the card values you have seen. The true count adjusts it for how many decks are left, so it means the same thing early and late in the shoe.
Does the true count work at online live blackjack?
Yes, at live dealer tables that deal from a real shoe, as long as you count from the shuffle. RNG games reshuffle every hand, so counting does nothing there.
Sources
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