Blackjack : Usually taking blackjack insurance is unprofitable

As expected, the casino doesn't want you to take advantage of situations where they are vulnerable because that will cost them money.

Situations like splitting sevens when the dealer has a 6, or doubling on 10 when the dealer has 5, are not preferred by the casinos and they don't want to encourage you to do so.

One blackjack possibility they promote is insurance mainly because it puts them at an advantage most of the time. But there are some situations when taking insurance is beneficial for the player too.

When the dealer's faced up card is an Ace, taking insurance is a good idea because you will win 2-to-1 if the dealer has blackjack.

There are six situations which can occur when you place $5 dollar insurance on a $10 bet:

1. Both the dealer and you have blackjacks. You will tie your original bet and win $10 on the insurance, meaning you win $10.

2. You have blackjack, but the dealer doesn't. You will win $15 on the original bet, but lose $5 on the insurance. You win $10.

3. The dealer has blackjack, but you don't. You lose your $10 original bet, but win $10 on insurance. It is a push; you don't win or lose anything.

4. You win the hand, but neither you nor the dealer have a blackjack. You win $10 on the original bet, but you lose $5 on insurance. You win $5.

5. You lose the hand, but neither you nor the dealer have blackjack. You lose both the $10 original bet and the $5 insurance. You loose $15.

6. You tie the hand, but neither you nor the dealer have blackjack. You tie the $10 original bet but you lose the $5 insurance. You loose $5.

So the results: three wins, a push, and two losses; "not too bad" many would say. Many would prefer placing insurance only when they have blackjack, thus avoiding the risk of a push or a loss. Despite these possibilities, the conclusions about insurance are uncertain.

What doesn't add up?
Insurance mainly represents a bet that the hole card is a 10. That’s all that matters when placing insurance. The odds are 9 to 4 against the hole card being a 10, because for the four 10 valued cards there are other 9 cards which could come.

To make it even simpler, let's say that you place 1300 insurances, an insurance being $5. From those 1300 insurances, you would lose 900 and win 400. When you win, you would win $10, meaning $4000 (400X10$). When you lose you would lose $5, meaning $4500 (900X5$). You would end up losing $500.

Is insurance profitable?
If instead of the 9 other cards would be 8, then insurance would be fair. If the possibilities would be less than 8, you would have the edge. The card counters often look for shoes that have an increased number of 10 cards, most preferably to be at least three 10 valued cards left.