When to double down in blackjack

What double down means

After the initial deal, a permitted double normally adds a stake equal to the original and deals one more card. You do not keep hitting after that card.

Hard-hand examples

In the default 4–8 deck S17 chart, hard 9 doubles against 3 through 6. Hard 10 doubles against 2 through 9. Hard 11 doubles against 2 through 10, but hits against an ace.

Rules shift these lines. With H17, hard 11 also doubles against an ace, and with one or two decks hard 9 doubles against a 2 as well. The single-deck chart adds hard 8 against 5 or 6.

Soft doubles and fallbacks

A,7 against 6 is Ds: double if allowed, otherwise stand. A,6 against 6 is Dh: double if allowed, otherwise hit. The second letter matters.

Double after split

DAS allows doubling after splitting a pair. Removing this option can also change whether the pair should be split in the first place. Use the matching chart setting, or check a hand in the blackjack calculator.

When can you double down?

The charts assume doubling is allowed on any first two cards, with a separate setting for doubling after a split. Some tables allow doubles only on selected totals. After a hit, a two-card double is no longer available: follow the chart’s hit or stand fallback.

If your original wager is $10, a full double adds $10 for $20 at risk. You receive one final card. An ordinary win then earns $20 profit on the combined wager; a loss loses the $20. Doubling the stake does not double the chance of winning.

Soft-hand doubling chart

Soft totals need their own reference. Under these default multi-deck S17 rules, A,2 and A,3 double against 5–6; A,4 and A,5 against 4–6; A,6 against 3–6; A,7 against 3–6. A,7 uses a stand fallback; the smaller soft doubles use a hit fallback. H17 and fewer decks can change these rows.

See the full soft-hand basic strategy chart for every dealer upcard and the rule-selectable blackjack chart for H17 or other supported combinations.