In blackjack, double down means you double your original bet after seeing your first two cards, and in return you get exactly one more card and then must stand.

Quick example

If you bet $10, doubling down means you add $10 more. Then the dealer gives you one final card, and your hand is locked in.

When players usually do it

Players often double down when their starting hand is strong enough that one more card could put them in a great position, such as totals like 9, 10, or 11 against a weaker dealer card.

Simple way to think about it

  • Hit: take another card, and you can keep deciding.
  • Double down: risk more money, but you only get one card and then stop.

If you want, I can also give you a beginner-friendly blackjack strategy chart for when to double down.