Should you double 11 against a dealer ace?
Double when the dealer hits soft 17. In a shoe game where the dealer stands on soft 17, just hit.
Expected result per unit bet on a 6-deck table where the dealer hits soft 17, with surrender (the common Las Vegas Strip game): Double +0.1240 · Hit +0.1087.
Practice on this table in the trainerBasic strategy chart for this table
The hand
You
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Dealer
| Play | Expected result |
|---|---|
| DoubleBest | +0.1240 |
| Hit | +0.1087 |
| Surrender | −0.5000 |
| Stand | −0.5951 |
Average win or loss per unit of the original bet (−0.5000 loses half the bet on average), computed exactly from the cards left in the shoe, with perfect play afterwards. In US games the numbers are after the dealer has checked for blackjack.
Why
Against an ace, 11 is a close call between doubling and hitting, and the soft 17 rule tips it. In single- and double-deck games the cards you hold matter more and doubling wins on the tables below. With no hole card (European rules) you would lose the doubled bet to a dealer blackjack, so hit.
Do the table rules change the answer?
The answer changes on 2 of the 7 tables below, highlighted.
| Table | Double | Hit |
|---|---|---|
| 6 decks · H17 · DAS · surrender | +0.1240 | +0.1087 |
| 6 decks · S17 · DAS · surrender | +0.1297 | +0.1476 |
| 8 decks · H17 · DAS · surrender | +0.1188 | +0.1072 |
| 2 decks · H17 · DAS | +0.1667 | +0.1211 |
| 1 deck · H17 · no DAS | +0.2343 | +0.1430 |
| 1 deck · S17 · no DAS | +0.2403 | +0.1729 |
| European: 6 decks · S17 · DAS · no hole card | −0.5319 | −0.2089 |
H17: the dealer hits soft 17. S17: the dealer stands on soft 17. DAS: you can double after splitting. European tables have no hole card, so the dealer only checks for blackjack after you play: those numbers include losing everything you bet to a dealer blackjack. They also allow doubling on 9 to 11 only and one split.