How insurance settles
When the dealer shows an ace, insurance commonly permits a wager up to half the original bet. It wins 2:1 if the dealer’s hole card has ten value and loses otherwise. The original blackjack hand then settles separately.
A half-unit insurance bet wins one unit of profit when the dealer has blackjack. That offsets the original one-unit loss on a non-blackjack hand, but the protection has its own price.
The break-even probability
A 2:1 wager breaks even when it wins one time in three: (1/3 × 2) − (2/3 × 1) = 0. If the probability of a ten-value hole card is below one-third, the insurance wager has negative expectation.
As a baseline before accounting for the player’s cards, removing only the dealer ace from a fresh deck leaves 16 ten-value cards among 51 cards, or about 31.37%. The player’s cards and every other exposed card shift that fraction. Basic strategy normally declines insurance because it does not track the full remaining composition.
Even money is not different
When the player has a natural against a dealer ace, taking even money guarantees a 1:1 profit. Mechanically, it is equivalent to receiving the normal 3:2 result while placing the maximum insurance wager.
Declining even money keeps the higher 3:2 payoff when the dealer lacks blackjack and pushes when the dealer has it. Under normal basic-strategy assumptions, declining has the higher expected value even though its outcome is less certain.
When composition matters
A card counter can sometimes identify a remaining deck unusually rich in ten-value cards, making insurance favorable. That is a composition-dependent decision, not a contradiction of basic strategy.
Side-counts, continuous shuffling machines, penetration, and the counting system all affect such an analysis. This guide does not provide a card-counting recommendation or claim that any particular casino permits advantage play.
Keep the wagers separate
- Insurance concerns only dealer blackjack
- It can lose even when the original hand wins
- Even money is maximum insurance on a natural
- The standard 2:1 payout needs a one-third win rate to break even
- A hunch about the next card is not composition analysis
The break-even calculation assumes insurance pays 2:1. Any different payout requires a new threshold. Last reviewed September 20, 2026.