Lesson 10 of 10 · 5 min
Lesson 10: card counting, without the myths
Key takeaway: Hi-Lo: 2–6 count +1, 7–9 zero, tens and aces −1. It’s legal, but the edge is small and it doesn’t work online.
Card counting means keeping track of the cards that have been dealt, so you know when the remaining cards are rich in high cards — which favor the player: more blackjacks, better doubles and a dealer who busts more.
The Hi-Lo system
| Cards | Value |
|---|---|
| 2 to 6 | +1 |
| 7 to 9 | 0 |
| 10, faces and ace | −1 |
The running total is the running count. Divided by the decks left to be dealt, it’s the true count. The higher it is, the more you bet.
The truth about the edge
A disciplined counter with good rules gets roughly 0.5–1% on money wagered, with enormous swings and a big bankroll behind it. Casinos shuffle early or ask you to stop playing once they spot you. It’s not a business plan.
Where it doesn’t work
- Online RNG blackjack: the deck is reshuffled every hand.
- Continuous shuffling machines: cards go back in after every hand.
Counting in your head is legal; using any device at the table isn’t. To practice, try the drills in how to practice card counting.
Congratulations
You’ve finished the course. You now know more than most people who sit down at a table. What’s left is turning it into reflex: deciding correctly in two seconds, hand after hand. The only way there is practice.