Basic Strategy Deviation Calculator
Advanced blackjack tool for card counters. Enter your hand, dealer upcard, and true count to see the optimal deviation and the threshold index.
Deviation Calculator Tool
Basic strategy: --
Deviation: --
📘 How to Use the Deviation Calculator
Hard hand (any total without Ace counted as 11), Soft hand (includes Ace valued at 11), or Pair (candidates for splitting).
The options will update based on hand type.
True count = running count ÷ remaining decks.
The tool shows the recommended action, the basic strategy action, and the index number where deviation begins. You'll see whether the current true count meets the threshold.
♠️ Understanding Strategy Deviations
- Index Number: The true count at which you should deviate from basic strategy. For example, insurance is taken at +3 or higher.
- Illustrious 18: The 18 most valuable deviations, accounting for most of a card counter's edge.
- True Count: Crucial for accurate play; use our calculator to ensure correct adjustments.
- Practice: Combine with our blackjack trainer to reinforce correct play.
🎯 Key Deviations (Illustrious 18)
Insurance
16 vs 10
15 vs 10
12 vs 2
12 vs 3
10 vs 10 (double)
❓ Frequently Asked Questions
What are basic strategy deviations?
Deviations are adjustments to basic strategy based on the true count in card counting. When the count is high, you may hit or stand differently because the remaining deck is rich in high cards.
How do I use this deviation calculator?
Select your hand type (hard, soft, or pair), choose your hand total and dealer's upcard, and enter the true count. The tool will tell you the recommended action and the index number for deviation.
What is the Hi-Lo system?
Hi-Lo is the most common card counting system: 2-6 = +1, 7-9 = 0, 10-Ace = -1. The true count is the running count divided by the number of remaining decks.
What is the Illustrious 18?
The Illustrious 18 are the 18 most important strategy deviations in blackjack. They provide the majority of the edge for card counters.
Is this deviation calculator free?
Yes, our deviation calculator is completely free. Use it to refine your blackjack strategy.
How do I interpret the true count?
True count = running count ÷ remaining decks. For example, with a running count of +6 and 2 decks left, true count = +3. Our calculator uses integer true count values.
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