What Is Doubling Down?

When you double down:

  1. You double your original bet
  2. You receive exactly one more card
  3. Your turn ends — no more hitting

Doubling down is the most powerful offensive tool in blackjack. It lets you maximize your bet in situations where you’re likely to win.

When to Double: Hard Hands

Double on Hard 11

Double against every dealer card (except Ace in multi-deck games).

Why it works: With 11, any 10-value card gives you 21. There are more 10-value cards in the deck than any other value. You’ll often end up with 19, 20, or 21 — strong totals against any dealer card.

Dealer Shows Single Deck Multi-Deck (4-8)
2-10 Double Double
Ace Double Hit

Double on Hard 10

Double against dealer 2 through 9.

Why: Same logic as 11, but slightly weaker since you need a face card or 10 for 20 (vs. 21 with 11). Against dealer 10 or Ace, the risk is too high.

Double on Hard 9

Double against dealer 3 through 6 only.

Why: A total of 9 is decent but not as strong as 10 or 11. You only double against the weakest dealer cards where the dealer is most likely to bust.

Hard 8 or Below

Never double. These totals aren’t strong enough to justify locking in one more card.

When to Double: Soft Hands

Soft hand doubles are where many players leave money on the table. Since you can’t bust on the next card, doubling soft hands against weak dealer cards is very profitable.

Soft 13-14 (A+2, A+3)

Double against dealer 5-6. Hit everything else.

Soft 15-16 (A+4, A+5)

Double against dealer 4-6. Hit everything else.

Soft 17 (A+6)

Double against dealer 3-6. Hit everything else.

This is a critical play. Many players stand on soft 17, but standing is a significant mistake. Doubling maximizes value against weak dealer cards.

Soft 18 (A+7)

Double against dealer 3-6. Stand against 2, 7, 8. Hit against 9, 10, A.

Soft 19 (A+8)

Double against dealer 6 only. Stand against everything else.

Soft 19 is strong enough to stand in nearly every situation. The one exception is dealer 6 — the weakest dealer card — where squeezing out extra value through doubling is correct.

Expected Value of Doubling

The reason to double is simple: you’re betting more money in favorable situations.

Your Hand Dealer Card EV of Hitting EV of Doubling
11 6 +0.67 +1.24
11 5 +0.67 +1.26
10 6 +0.50 +0.97
Soft 18 5 +0.34 +0.56

EV = Expected Value per dollar wagered. Higher is better.

When EV of doubling > EV of hitting, you should double. These situations are why doubling is so important to your bottom line.

Doubling After Splits

If the table allows Doubling After Splits (DAS), you can double down on a hand created by splitting.

Example: You split 3-3 against a dealer 5. Your first hand receives an 8, giving you 11. You double down on 11 against 5 — an excellent situation.

DAS makes some marginal splits profitable:

  • Splitting 2s-3s against dealer 2-3 (becomes profitable with DAS)
  • Splitting 4s against dealer 5-6 (becomes profitable with DAS)
  • Splitting 6s against dealer 2 (becomes profitable with DAS)

Rules Variations

Not all casinos offer the same doubling rules:

Rule Effect
Double on any two cards Best for players (standard)
Double on 9, 10, 11 only Costs ~0.09% edge
Double on 10, 11 only Costs ~0.18% edge
No doubling after splits Costs ~0.14% edge
Double on any number of cards Rare; benefits players

Always check the table rules before sitting down. The ability to double on any two cards and after splits is important for keeping the house edge low.

Key Takeaways

  1. Always double 11 (except vs. Ace in multi-deck)
  2. Always double 10 against 2-9
  3. Double 9 against 3-6
  4. Double soft hands against weak dealer cards
  5. Never skip a double opportunity — these are your profit plays
  6. Look for tables that allow doubling on any two cards and DAS