In blackjack, you should double down when your starting two‑card hand has a strong chance of beating the dealer with just one extra card, especially when the dealer is showing a weak up‑card. Below is a clear, practical guide for standard multi‑deck games where you can double on any two cards and the dealer stands on soft 17.

Quick scoop: when to double down

  • Hard 11 vs dealer 2–10 → double down (almost always).
  • Hard 10 vs dealer 2–9 → double down.
  • Hard 9 vs dealer 3–6 → double down.
  • Soft hands (Ace + 2–7) vs dealer 4–6 (sometimes 3–6) → double if the table allows soft doubles.

Hard‑hand doubling (no Ace)

A “hard” hand is any total without an Ace, or where the Ace must count as 1.

  • Hard 11
    • Double vs dealer 2–10 ; hit vs dealer Ace (because the dealer may already have blackjack or a strong hand).
  • Hard 10
    • Double vs dealer 2–9 ; hit vs 10 or Ace.
  • Hard 9
    • Double vs dealer 3–6 ; hit vs 2 or 7–A.

Soft‑hand doubling (Ace involved)

Soft hands are flexible because the Ace can be 1 or 11.

  • Ace‑2 or Ace‑3 (soft 13–14) → double vs dealer 5–6.
  • Ace‑4 or Ace‑5 (soft 15–16) → double vs dealer 4–6.
  • Ace‑6 (soft 17) → double vs dealer 3–6.
  • Ace‑7 (soft 18) → double vs dealer 2–6 in many rule sets.

Always check the table rules: some casinos restrict doubling to 9–11 only , which removes many soft‑hand doubles.

When not to double down

  • Your total is 12 or more with a weak or medium dealer card (e.g., hard 12 vs 4–6 is usually a hit, not a double).
  • Dealer shows 10 or Ace , unless your hand is one of the standard doubles above (e.g., hard 11 vs Ace is usually a hit, not a double).
  • You have a weak soft hand (like Ace‑2 vs dealer 2–4) and the dealer isn’t in a clear bust range.

Simple reference table (standard rules)

[1][7][3] [1][3] [1][3][5] [3][1] [5][3] [3][5] [9] [9] [9] [9]
Your hand Dealer up‑card Action
Hard 11 2–10 Double down
Hard 11 A Hit
Hard 10 2–9 Double down
Hard 10 10, A Hit
Hard 9 3–6 Double down
Hard 9 2, 7–A Hit
Soft 13–14 (A‑2, A‑3) 5–6 Double down
Soft 15–16 (A‑4, A‑5) 4–6 Double down
Soft 17 (A‑6) 3–6 Double down
Soft 18 (A‑7) 2–6 Double down in many rule sets
If you tell me the exact rules at your table (number of decks, dealer hits/stands on soft 17, doubles allowed on which totals), I can give you a tighter, tailored “when to double down” chart for that specific game.

Information gathered from public forums or data available on the internet and portrayed here.