Learn the mathematics behind card counting systems
⚠️ Educational Purpose Only
This tool teaches the mathematics of card counting for educational purposes. Card counting is legal to learn but using it in casinos may result in being asked to leave. This app is for understanding probability theory only.
Practice Counting
K♠
0
True Count: 0.0
Decks Remaining: 6.0
What value should you add to the count?
0
Cards Shown
0
Correct
0%
Accuracy
0.0s
Avg Speed
Hi-Lo System (Most Popular)
The Hi-Lo system is the most widely used card counting system. It's balanced, relatively simple, and effective.
Cards
Count Value
Reason
2, 3, 4, 5, 6
+1
Low cards favor dealer
7, 8, 9
0
Neutral cards
10, J, Q, K, A
-1
High cards favor player
How It Works:
Running Count: Add/subtract values as cards are dealt
True Count: Running count ÷ decks remaining
Positive Count: More high cards left (player advantage)
Negative Count: More low cards left (dealer advantage)
Why Card Counting Works (Mathematics)
Card counting exploits the fact that the probability of drawing certain cards changes as cards are removed from the deck.
Key Concepts:
Dependent Events: Each card dealt changes the composition of the remaining deck
High Card Advantage: More 10s and Aces increase blackjack probability and double down success
Dealer Bust Rate: Increases when more high cards remain (dealer must hit to 17)
Expected Value Shift: True count of +1 ≈ 0.5% player advantage
Example: With a true count of +4, the player has approximately a 2% advantage over the house. This is why casinos don't like card counters - the math actually works!
Practice Tips
Start slow - accuracy is more important than speed
Practice until you can count without thinking
Learn to count pairs (e.g., K+5 = 0, cancel each other out)
Master running count before worrying about true count
Aim for 95%+ accuracy before increasing speed
Remember: This is educational - understanding the math is the goal