I'm on a website that if I get a 21 on 3 or more cards,I automatically win except dealer bj. How much does this help me if basic strategy gives me a negative half percent
Can you describe how you get your answer? I'm getting more like 0.52%, which would represent when player and dealer tie with non-blackjack 21. That's the edge: getting paid on those hands, when normally you would push. Or so it seems to me.
Don
Let me try this. learn to post. What I find out is 0.04%.
Here is my calculation:
1. Probability of dealer 21: 6.7%;
2. Probability of dealer non blackjack 21: 1.9%;
3. Probability of player non blackjack 21: 1.9%;
4. Probability of both non blackjack 21: 0.04%;
This mean a positive advantage of 0.04%
You have no understanding of what you're doing. I gave you the correct values above. Didn't you read what I wrote? Or did you just figure I was wrong?
Don
Now, I can sleep tonight. My work has been validated. You agree with me. Big relief for me.
Don
Well, of course a) no one plays infinite deck, and b) the player doesn't use the same rules as the dealer! Other than that, just fine! 
Don
Well, of course a) no one plays infinite deck, and b) the player doesn't use the same rules as the dealer! Other than that, just fine!
Don
These do not sound reasonable for me. On your first point, most of the today’s blackjack games can be treated as infinite decks. All of the online blackjack and casino CSM blackjacks are exactly infinite decks, and even 6 and 8 decks can be regarded as infinite decks too. On your second point, there is very little difference between the dealer and the player in terms of the final hand probability of a non-blackjack 21.
