Why Double 11 vs Dealer 6 in Blackjack?
Hard 11 is the strongest doubling hand in the game. A dealer 6 is the weakest upcard. Together, this is one of the clearest doubles in basic strategy. Here are the actual numbers.
Short answer
Double. Hard 11 is a double against every dealer upcard from 2 through 10. Dealer 6, the upcard with the highest bust probability, is where doubling 11 is worth the most. Against a dealer Ace the answer depends on the soft-17 rule: hit if the dealer stands on soft 17, double (by a hair) if the dealer hits soft 17.
The probability and EV comparison
These are the numbers the trainer shows for hard 11 (for example 6 + 5) against a dealer 6. The site's default rules apply: dealer stands on soft 17, late surrender allowed. A dealer 6 can't have blackjack, so there is no separate before/after-peek figure.
| Action | Win | Push | Lose | EV |
|---|---|---|---|---|
| DOUBLE | 63.3% | 6.7% | 30.0% | +0.667 |
| HIT | 63.3% | 6.7% | 30.0% | +0.334 |
| STAND | 42.3% | 0.0% | 57.7% | -0.154 |
Double and hit have the same win, push and lose chances here. That's no coincidence. Against a dealer 6, the best play after hitting 11 is to stand on whatever you get, so hitting plays out exactly like doubling, with half the money on the table. Doubling simply doubles a hand that already wins 63.3% of the time: +0.667 instead of +0.334, about 33¢ more per $1 of your original bet.
Hard 11 against every upcard
| Dealer upcard | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | A |
|---|---|---|---|---|---|---|---|---|---|---|
| Double EV | +0.471 | +0.518 | +0.566 | +0.615 | +0.667 | +0.463 | +0.351 | +0.228 | +0.089 | -0.232 |
| Hit EV | +0.238 | +0.260 | +0.283 | +0.307 | +0.334 | +0.292 | +0.230 | +0.158 | +0.033 | -0.209 |
| Best | DOUBLE | DOUBLE | DOUBLE | DOUBLE | DOUBLE | DOUBLE | DOUBLE | DOUBLE | DOUBLE | HIT |
Dealer stands on soft 17. The values for a dealer 10 or Ace include the chance that the dealer has blackjack, as the trainer shows them. Under H17 the Ace column flips to a double, but only just: -0.236 for doubling vs -0.237 for hitting.
Why 11 is the strongest hand to double
A hard 11 can reach 21 with any ten-value card, the single most common card value in the deck, and it cannot bust on the very next card no matter what's drawn. That combination, unable to bust while having a high chance of a great total, is exactly what makes doubling profitable: you're putting a second bet behind a hand that rarely gets worse and often gets much better.
Why dealer 6 makes it even better
A dealer 6 busts 42.3% of the time, more often than any other upcard, because the dealer must keep hitting any total under 17 with no choice in the matter. Doubling here means committing a bigger bet at exactly the moment the dealer is most likely to bust. That's why the table above peaks at the 6 column.
Why the range narrows below 11
As the two-card total drops from 11 to 10 to 9, the odds get gradually less favorable, and the doubling range narrows to match: hard 10 doubles against a dealer 2 through 9, and hard 9 only against a dealer 3 through 6. Hard 11 is the one total strong enough to double against nearly every dealer upcard. In a real 6-deck shoe, doubling 11 against a 6 is worth even a little more (about +0.683), because your 6 and 5 and the dealer's 6 leave the shoe slightly richer in ten-value cards. The numbers above come from the site's probability engine, which uses an infinite-deck approximation. See the full basic strategy chart for the exact line on every hard total, or read Double Down for the complete reasoning.
Confirm it yourself
The trainer shows the probability and expected value of doubling vs. hitting for this exact matchup, so you can see the gap for yourself instead of taking it on faith.
Practice Double Down Decisions