Blackjack Insurance Bets
Blackjack tables typically display the main rules, payouts and terms for an insurance wager. It may seem odd for a casino to prominently promote a side bet that appears to protect players, since casinos generally feature options that favour the house. That's a good reason to take a closer look. Insurance can sound like a way to improve a player's position, but its presence at the table doesn't make it a favourable bet.
What Is the Insurance Bet?
Despite its name, insurance doesn't protect your current blackjack hand. It's a separate side bet offered when the dealer's exposed card is an ace.
At this point, the dealer asks whether players want to insure against the possibility of the dealer having a natural blackjack. Taking the offer is entirely optional.
If you take insurance, you can wager any amount up to half your original bet. You may bet less than half, but not more.
Insurance pays 2 to 1. If you wager half your original bet and the dealer has a natural blackjack, the insurance payout equals your initial bet, offsetting the amount lost on your main hand.
What's the Problem with the Insurance Bet?
Professional blackjack players often call insurance a “suckers’ bet” because the dealer gets blackjack less than a third of the time. That means players lose on more than two thirds of these side bets.
The bet is essentially a wager that the dealer's hidden card is worth 10. In a 6-deck or 8-deck game, the average distribution is 4 10-value cards for every 9 cards that aren't worth 10.
These proportions mean the odds are 9 to 4 against the dealer having a 10-value hole card. Consider a $10 blackjack hand and a long session where you take insurance 130 times at $5 each.
Your 130 side bets would add up to $650. With a statistically even distribution of cards, you would win 40 bets, earning 40 x $10 = $400, and lose the other 90, for a cost of $450. That would leave you $50 down on insurance.
When Should You Make the Insurance Bet?
A 2 to 1 payout can make insurance tempting, but the bet is usually worthwhile only when card counting shows an unusually high proportion of 10-value cards in the deck. With 4 10-value cards for every 9 other cards, the player is still at a disadvantage.
At a ratio of 4 10-value cards to 8 other cards, neither side has an edge, making insurance a fair bet.
If there are 4 10-value cards for every 7 or fewer other cards, the advantage moves to the player and insurance becomes worthwhile.
If you don't count cards, it's generally best to turn down insurance. Casino Ideal's review notes one possible exception: when more than 5 blackjack hands are dealt in a round and no player has a 10-value card, the chance of a 10-value hole card is higher than usual, so taking insurance may be justified.
A Few Words of Caution
Card counting doesn't help in software-based blackjack at an online casino. The software automatically shuffles after each hand, so no cards stay out of play. For example, every hand in an 8-deck game uses the full 8 decks.
As a result, each hand in software-based blackjack has the same odds as the one before, making insurance unfavourable. Casino Ideal's review recommends counting only when playing at a land-based casino or at an online live-dealer blackjack table where dealt cards are discarded; the odds may then change as the shoe is played, until it is reshuffled.
A positive expectation means the odds favour you over time; it doesn't guarantee a win on any particular bet.
Circumstances that make insurance favourable are unusual. Casino Ideal's review notes that many blackjack games don't deal far enough into the shoe, reshuffling when 3 decks remain.
Your estimate of how many decks remain in the shoe matters too. Miscounting them can give you an inaccurate assessment of the odds.
