Blackjack Insurance Bets
Blackjack tables commonly display the game’s main rules, payouts and the terms for an insurance wager. Seeing a casino prominently advertise a side bet that appears to protect players can seem puzzling: casinos generally feature options that favour the house. That’s a reason to examine the bet closely. Insurance may sound like a way to improve a player’s position, but its presence on the table does not make it a favourable wager.
What is the Insurance Bet?
Despite its name, insurance does not protect your current blackjack hand. It is a separate side bet offered when the dealer’s exposed card is an ace.
At that point, the dealer asks whether players want to insure against the dealer having a natural blackjack. Taking the option is entirely voluntary.
If you choose insurance, your side wager may be any amount up to half of your original bet. You can stake less than half, but the wager cannot exceed that limit.
The insurance payout is 2 to 1. If you stake half your original wager and the dealer has a natural blackjack, the doubled insurance return equals your initial bet, offsetting the amount lost on the main hand.
What is wrong with the Insurance Bet?
Insurance is often called a “suckers’ bet” by professional blackjack players because the dealer makes blackjack less than a third of the time. In other words, players lose more than two thirds of these side wagers.
The bet is effectively a wager that the dealer’s hidden card has a value of 10. In a 6-deck or 8-deck game, the average distribution is 4 10-value cards for every 9 cards that are not worth 10.
Those proportions put the odds at 9 to 4 against a 10-value hole card. Consider a $10 blackjack hand and a long session in which you buy insurance 130 times for $5 each time.
Your 130 side bets would total $650. With a statistically even card distribution, you would win 40 bets, earning 40 x $10 = $400, and lose the other 90, costing $450. The result would be a $50 loss on insurance.
When to make the Insurance Bet?
A 2 to 1 return can make insurance appealing, but the wager is generally worthwhile only when card counting indicates that the deck contains an unusually high share of 10-value cards. At 4 10-value cards for every 9 other cards, the player remains at a disadvantage.
At a ratio of 4 10-value cards to 8 other cards, neither side has an advantage, so insurance is a fair bet.
If the ratio drops to 4 10-value cards for 7 or fewer other value cards, the advantage shifts to the player and insurance becomes worthwhile.
Without counting cards, it is generally best to decline insurance. The review describes one possible exception: when more than 5 blackjack hands are dealt in a round and no player shows a 10-value card, a 10-value hole card is more likely than usual, so taking insurance may be justified.
Some Words of Caution
Card counting is not useful in software-based blackjack at an online casino. The software automatically shuffles after each hand, so no cards remain out of play. For example, in an 8-deck game each hand uses the full 8 decks.
As a result, software-based blackjack gives each hand the same odds as the previous one, leaving insurance unfavourable. The review suggests counting only when playing in a land casino or at an online live-dealer blackjack table where dealt cards are discarded; the odds can then shift as the shoe is played, until it is reshuffled.
A positive expectation means the odds favour you over time; it does not promise a win on any individual bet.
Conditions that make insurance favourable are uncommon. The review says that many blackjack games do not deal deep enough into the shoe, with a reshuffle when 3 decks remain.
Your estimate of the number of decks left in the shoe also matters. Misjudging how many remain can lead to an inaccurate reading of the odds.
