To take insurance or not take insurance. It’s a decision that becomes tougher for players when they have a good hand, particularly blackjack. The more money on the line, the more likely players are to take insurance. This is where players go wrong. Insurance is not a wager you should take to “protect” your original bet. It is striclty a side bet on whether or not the dealer has a ten or face card in the hole. Players can insure their bets by placing an amount up to half their wager in the insurance area on the table. If the dealer does have a ten or face card in the hole, the bet pays off 2 to 1.
Let’s break down the expected win of insurance for a 6-deck shoe. When the dealer shows an ace, the odds she will have blackjack are 96/311. There are 96 ten-value cards in a 6-deck shoe and there are 312 total cards in a 6-deck shoe (52 x 6). Not counting the ace showing there are 311 cards remaining. There is a 96/311 chance that the dealer will flip over a ten or face card and pay off insurance bets 2 to 1. There is a 215/311 chance that the dealer will not have blackjack and all insurance bets will lose.
Based on a $100 bet, here is how the expected win works out.
(96/311) x ($200) + (215/311) x (-$100) = $(19200/311) –
$(19200/311) – $(21500/311) = -$(2300/311)
Over the long run, for every $100 you wager on insurance you can expect to lose $7.395 . The insurance bet has a 7.395% house edge. To put this in perspective, the house edge on insurance is more than 14 times the edge versus a basic strategy player, playing at a .5% disadvantage. This is why one of the cardinal rules of basic strategy is never take insurance. So the next time someone tells you to take even money, remember, the only sure thing about insurance is that it will cost you a pretty penny over the long run.