Should you take insurance in blackjack?
No. Insurance loses money unless you count cards, and even money on a blackjack is the same bet.
On a 6-deck table where the dealer hits soft 17, with surrender (the common Las Vegas Strip game), insurance on a 10-7 averages −0.0388 per unit bet, −7.77% of what you put on insurance.
Practice on this table in the trainerBasic strategy chart for this table
The hand
You
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Dealer
| Play | Per unit bet |
|---|---|
| DeclineBest | 0.0000 |
| Take insurance | −0.0388 |
Insurance costs half the original bet and pays 2 to 1 if the dealer has blackjack. The value is per unit of the original bet; "per insurance bet" divides it by the half unit you put up. Declining costs nothing.
Why
Insurance pays 2 to 1, so it only breaks even if the dealer has a ten under the ace at least one time in three. Fewer than a third of the cards are tens, and every ten in your own hand lowers the chance a little more. Even money on a blackjack is insurance under another name: it trades an average of more than one bet for exactly one.
Does the number of decks change it?
| Table | Ten in the hole | Per unit bet | Per insurance bet |
|---|---|---|---|
| 6 decks · H17 · DAS · surrender | 30.74% | −0.0388 | −7.77% |
| 8 decks · H17 · DAS · surrender | 30.75% | −0.0387 | −7.75% |
| 2 decks · H17 · DAS | 30.69% | −0.0396 | −7.92% |
| 1 deck · H17 · no DAS | 30.61% | −0.0408 | −8.16% |
H17: the dealer hits soft 17. S17: the dealer stands on soft 17. DAS: you can double after splitting.
Does your hand change it?
| Your hand | Ten in the hole | Per unit bet | Per insurance bet |
|---|---|---|---|
| 10-7 | 30.74% | −0.0388 | −7.77% |
| 10-K | 30.42% | −0.0437 | −8.74% |
| 9-8 | 31.07% | −0.0340 | −6.80% |
| 5-6 | 31.07% | −0.0340 | −6.80% |
| A-K | 30.74% | −0.0388 | −7.77% |
Against the same dealer card, on 6 decks · H17 · DAS · surrender.
Even money on a blackjack
Taking even money on a blackjack is worth exactly +1.0000 per unit bet. Declining it is worth +1.0388 on average: you are paid 3 to 2 unless the dealer also has blackjack, which pushes.