Should You Take Insurance?

When the dealer shows an ace, you are offered insurance: a side bet, up to half your original wager, that pays 2 to 1 if the dealer has blackjack. It is presented as protection. It is not protection, and the name is doing a lot of work.

Insurance is a standalone bet on one question: does the dealer have a ten-value card underneath? Your own hand is irrelevant to it, which is the first thing to understand.

The arithmetic

Sixteen of the fifty-two ranks in a deck are ten-value: tens, jacks, queens and kings. That is roughly 30.8 percent of the remaining cards, so the dealer completes blackjack a little under a third of the time.

The bet pays 2 to 1, which would be break-even at 33.3 percent. At 30.8 percent it is not break-even, and the gap is the house edge, which is about 7 percent on the insurance wager. That is several times worse than the edge on the main game.

"But I have 20"

A strong hand makes insurance feel more urgent and changes nothing about the math. Your 20 does not alter what is under the dealer's ace.

In fact holding a 20 makes insurance slightly worse, because two of your own cards are ten-value, leaving marginally fewer in the deck for the dealer.

"Even money" is the same bet

If you have a blackjack and the dealer shows an ace, you will be offered "even money", which is a guaranteed 1 to 1 payout instead of the 3 to 2 you would get if the dealer does not have blackjack.

That is insurance wearing a different name. Taking it costs you about the same 7 percent over time. Decline it, accept that you will occasionally push a blackjack, and come out ahead across the long run.

When insurance is actually correct

There is one case, and it does not apply to basic strategy play. A card counter tracking the ratio of tens remaining can identify decks rich enough in ten-value cards to push the true probability above 33.3 percent, at which point insurance becomes positive expectation.

That requires counting through a shoe accurately, and it is the single most valuable bet available to a counter. If you are not counting, the condition never arises for you.

Why casinos offer it

Insurance is offered enthusiastically for the same reason side bets generally are: the house edge on it dwarfs the edge on the main game. A player who takes insurance regularly gives back far more than one who never does.

Declining it costs you nothing and takes no discipline beyond ignoring the prompt.

The rule

Decline insurance every time. Decline even money every time. There is no hand, no streak and no situation in basic strategy play where either is the right call.

For the correct play on the hand itself, use the calculator or the full strategy chart.

A note on risk. Basic strategy reduces the house edge to roughly half a percent. It does not remove it. Nothing here is gambling advice or a prediction of results. If gambling has stopped being entertainment, the National Problem Gambling Helpline is 1-800-522-4700, or ncpgambling.org.