Doubling is where blackjack pays you back for the hands you lose. Here is when to do it at our table, and what each double is worth.
Double hard 11 against every dealer card except an ace, hard 10 against 2–9 and hard 9 against 3–6. Double soft 13–14 (A,2 and A,3) against 5–6, soft 15–16 (A,4 and A,5) against 4–6, and soft 17–18 (A,6 and A,7) against 3–6. Never double hard 12 or more. Doubling right is worth about 1.5% of everything you bet.
Because you get only one card, a double is a bet that one card will be enough. That makes 9, 10 and 11 the natural candidates — many cards turn them into 19, 20 or 21 — and a weak dealer card the natural moment.
| Dealer shows | 11: double / hit | 10: double / hit | 9: double / hit |
|---|---|---|---|
| 2 | +48.2 / +24.4 | +37.0 / +18.8 | +7.0 / +7.7 |
| 3 | +53.0 / +26.6 | +42.3 / +21.2 | +13.3 / +10.7 |
| 4 | +58.0 / +29.0 | +47.6 / +23.8 | +19.8 / +13.7 |
| 5 | +63.1 / +31.6 | +53.1 / +26.5 | +26.4 / +16.9 |
| 6 | +67.7 / +33.8 | +58.6 / +29.3 | +32.9 / +20.2 |
| 7 | +46.6 / +29.3 | +40.1 / +26.0 | +11.6 / +17.6 |
| 8 | +34.9 / +22.9 | +29.1 / +20.0 | −2.1 / +10.0 |
| 9 | +22.7 / +15.6 | +14.7 / +11.7 | −29.8 / −5.2 |
| 10 | +17.7 / +11.8 | −0.6 / +2.6 | −46.3 / −15.2 |
| Ace | +12.3 / +14.7 | −0.8 / +8.1 | −42.9 / −6.8 |
11 is the best hand to double: every ten-value card gives you 21. Against a 6, doubling 11 earns +67.7 per 100 debens of your original bet, twice what a plain hit earns.
10 stops being a double against a ten or an ace, where the dealer often reaches 20 or 21. 9 is a double only against 3–6, and against a 2 it is the closest cell in the table: hit +7.7, double +7.0.
Plenty of players double 11 against anything. At our table, against an ace, a plain hit is better: +14.7 per 100 against +12.3. The dealer has already checked and has no blackjack, but an ace still finishes on 17–21 more than four times in five. You want the option to take a second card if the first one is small.
The answer depends on the dealer’s soft 17 rule. Where the dealer hits soft 17, the ace becomes a little weaker and doubling 11 is right — our recalculation for those rules confirms it. Our dealer stands, so hit.
These are the doubles beginners miss. One card can’t bust a soft hand, and against a dealer showing a weak card it pays to put in a second bet even when your total is small:
| Hand | Double against | Example: double / next best |
|---|---|---|
| A,2 and A,3 (soft 13–14) | 5, 6 | A,2 against a 6: +18.8 / hit +16.3 |
| A,4 and A,5 (soft 15–16) | 4, 5, 6 | A,4 against a 4: +6.2 / hit +5.9 |
| A,6 (soft 17) | 3, 4, 5, 6 | A,6 against a 6: +25.9 / hit +12.9 |
| A,7 (soft 18) | 3, 4, 5, 6 — otherwise stand | A,7 against a 6: +38.3 / stand +28.0 |
Some of these are tiny edges: A,4 against a 4 earns three tenths of a deben more per 100 by doubling. Others, like A,6 against a 6, double your result. If you already hold three cards and can no longer double, hit soft 13–17 and stand on soft 18. There is more in soft hands.
Doubling too rarely is expensive, and so is doubling in the wrong spots. The common habits, as a share of everything you bet:
| Habit | Extra cost |
|---|---|
| Never doubling 11 | 0.74% |
| Never doubling 10 | 0.40% |
| Never doubling 9 | 0.08% |
| Never doubling soft hands A,2–A,6 | 0.06% |
| Doubling 10 against a ten | 0.03% |
| Standing on A,7 against 3–6 instead of doubling | 0.03% |
| Doubling 11 against an ace | 0.01% |
And never double a hard 12 or more. Against a 6, doubling 12 loses 34.1 per 100 debens of the original bet; standing loses 15.4. One ten-value card busts the hand, and then you lose twice the bet.
In the simulation, a player who follows the chart but never doubles faces a house edge of 1.95% instead of 0.43%. Doubling is worth 1.5% of everything you bet — more than splitting and declining insurance put together. The chart doubles in about one round in ten.
It also means a double needs debens in reserve. If your balance only covers the bet, you will have to hit when the chart says double. Betting no more than a tenth of your balance per hand leaves room for doubles and splits.
No. Doubling is only allowed on your first two cards, including the first two cards of a split hand.
Not at our table. A double always matches your original bet.
Yes. Doubling earns +17.7 per 100 debens of your original bet, hitting +11.8.
Any ten-value card busts 12, and then you lose twice the bet. Standing on 12 against a 6 loses 15.4 per 100; doubling would lose 34.1.
Yes, on any split hand except split aces, which get one card each.
The right move for every hand at our table, how we calculated it and what it saves.
Read more →How to tell them apart, why soft hands are played boldly, and the soft 17 and 18 traps.
Read more →Every pair against every dealer card, our split rules and what each split is worth.
Read more →Our 0.40%, how it was calculated, what every rule changes and how simple styles compare.
Read more →
At the Scribes’ Table a double costs as little as 100 debens. Watch for 11 against a 6 — the best hand there is to double.
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