Blackjack Card Counting Calculator
The Running Count Alone Doesn't Tell You Much
Hi-Lo card counting assigns +1 to every 2 through 6 dealt, 0 to every 7, 8, or 9, and −1 to every 10, face card, or ace. Keeping that running tally is only half the system, though — a running count of +8 means something very different in a freshly shuffled 6-deck shoe than it does with one deck left. Dividing by the decks remaining converts the raw tally into a "true count" that's comparable across any point in the shoe, which is what actually drives betting decisions.
The Formula
Decks remaining is estimated from the discard tray or by eye, then rounded to the nearest half or quarter deck — precision here matters, since dividing by 1 deck versus 2 decks remaining roughly doubles or halves the true count for the same running count.
What the True Count Implies
| True count | Deck composition | General guidance |
|---|---|---|
| +3 or higher | Rich in tens and aces | Strong player advantage — consider increasing bet size. |
| +1 to +2.9 | Slightly rich in tens and aces | Slight player advantage — modest bet increase. |
| −0.9 to +0.9 | Roughly balanced | Close to neutral — bet table minimum. |
| −1 or lower | Depleted of tens and aces | House advantage — bet minimum or sit out the shoe. |
These bands describe the general direction of the edge, not a fixed percentage — the exact edge shift per true count point varies by the specific table's rules, number of decks, and penetration.
Where This Gets Used
- Practicing the Hi-Lo system away from the table — converting a running count to a true count is the step most beginners get wrong, since it's easy to forget when the deck estimate changes mid-shoe.
- Comparing shoe penetration strategies — seeing how the same running count produces very different true counts at different points in the shoe illustrates why deep-penetration games are more exploitable.
- Blackjack strategy education — a clean way to demonstrate the mechanics behind bet spreading without needing a live shoe.
How to Use This Calculator
- Enter the Running Count you've kept using the Hi-Lo system (+1 per low card, −1 per high card).
- Enter Decks Remaining — the estimated number of decks left to be dealt in the shoe.
- Select Calculate to get the true count and general betting guidance.
Related Calculations
Working out the underlying deal probabilities instead? See the Blackjack Odds Calculator in the casino gambling section, or check overall randomness with the Deck Shuffle Randomness Calculator.