Imagine that there is a way to protect your blackjack wager. A sort of insurance that will cover your wager so that you do not lose it in case the dealer turns up that natural blackjack.
Such a thing exists. And it is called insurance in blackjack. But it is not as rosy of a picture as casinos would like for you to believe.
Insurance is offered when the dealer has an Ace for an up card. It is offered because an Ace is required for a natural blackjack, and is the less common of the two cards needed. So the feeling is that if the less common required card is present, there is a good chance that the hole card will have a value of 10.
This is what casinos would like for you to think. But let’s look at the statistics of that hole card being worth 10.
In blackjack there are only four cards worth 10: the 10 itself, the Jack, the Queen and the King. There are thirteen cards per suit and four suits per deck, so there are sixteen cards in a single deck that are worth 10. Of the possibilities that the hole card is worth 10, only sixteen out of the theoretical fifty one remaining cards will be worth 10. That means that there is only a 31% chance that the dealer’s whole card will be worth 10, giving him a natural blackjack. Therefore there is a 69% chance that the dealer will not have a natural blackjack.
Insurance is a side bet in which you wager half the amount of your original bet. If the dealer’s hole card is in fact worth 10 and he has a natural blackjack, you would lose your original wager, but collect on the side bet.
But you are a smart blackjack player, so why would you place a side bet for an outcome that the odds do not favor?
That is the case with the insurance side bet. You are wagering that the dealer’s hole card will be worth 10 when there is only a 31% chance of that happening.
The casino is glossing insurance over as something that will help you, when the odds of insurance actually helping you are a little less than a third of a reality. This is why experienced blackjack players will tell novices to decline insurance in blackjack—the odds truly are against the outcome favoring the player.