Dealer with an Ace, How Likely is it They Will Have a 10 Too?

One of the worst bets in blackjack is insurance. The exception to the aforementioned statement is side bets. Those surpass even insurance. But insurance in blackjack is based on scaring a player into protecting their wager.

It works like this: You are in a casino and playing some blackjack. The dealer’s up card is an Ace. There is a collective intake of breath from the other players at the table. If the hole card is a 10 it means the dealer has a natural blackjack and everyone loses. Except for those with a natural blackjack themselves, in which case they push and only get to keep their wager as opposed to receiving a 3-2 payout. It is a crappy situation all around. Once the dealer sees he has an Ace he will offer all the players insurance.

Insurance in blackjack is a separate wager that is equal to half the amount of your original wager. So if you wagered $50 your insurance wager is $25. If the dealer does indeed have a natural blackjack you would lose your original wager, but collect 1-1 on the insurance wager so that you would wind up with the amount of your original wager; but you will have still lost $50 and only received $25 from the house so that you are still out a negative net of $25. If the dealer does not have a natural blackjack the dealer will then collect your insurance wager. It all hinges on whether the dealer has a 10 for a hole card.

But what are the odds? Do the odds favor taking insurance or not?

There are only four cards with a value of 10 in blackjack. Four cards out of thirteen. That means there is only a 31% chance that the hole card will be a 10. The remaining 69% of the time the hole card will be worth something else. So based on that taking insurance is not worth the wager because the odds in blackjack are against the dealer having a 10 for the hole card.