When to Double Down in Blackjack — Strategy & EV

Doubling down lets you double your bet for exactly one more card. It is the single biggest way basic strategy adds value, because you put more money in precisely when you hold an edge — so doubling too little quietly costs you EV.

Hard-total doubles

• Hard 11 — double against 2–10. Against an Ace, double under H17 rules, otherwise hit.
• Hard 10 — double against 2–9. Just hit versus a 10 or Ace.
• Hard 9 — double against 3–6 only. Hit against everything else.

The pattern: you double when you are likely to draw a strong total and the dealer is likely to be in trouble.

Soft-total doubles

Soft hands (an Ace counted as 11) double against the dealer's weak cards, where the flexible Ace lets you draw without bust risk:

• A,2 / A,3 — double vs 5–6
• A,4 / A,5 — double vs 4–6
• A,6 — double vs 3–6
• A,7 — double vs 3–6 (otherwise stand vs 2/7/8, hit vs 9/10/A — see soft hands strategy)

Rules change the cut-offs

Doubling is only allowed on your first two cards, and double-after-split (DAS) availability shifts some pair and soft decisions. H17 games add a few doubles (e.g. hard 11 vs Ace).

In the strategy chart below, every blue “D” cell is a double. Notice the whole hard-11 row is blue (double against everything but an Ace), with hard 10 and 9 doubling against the dealer's weaker cards. The colours are computed live from the shoe, so they update as cards are removed:

Because the value of doubling is a direct EV comparison, the exact gain for your rules and shoe is always the number behind each cell.

Start from the basic strategy overview, or pick your exact game in the blackjack rule variants.