When should you double down in blackjack?
Doubling down is blackjack's aggression button: you double your bet in exchange for exactly one more card. Used at the right moments it is one of the biggest edges available to a player, but used carelessly it just throws away chips.
How doubling works
After your first two cards you can double your original bet, then take one - and only one - additional card. Your hand is then locked. Because you cannot draw again, doubling shines when your two cards give you a strong starting point like 10 or 11 and the dealer looks weak.
The best doubling hands
Basic strategy says double a hard 11 against nearly every dealer upcard, double a hard 10 unless the dealer shows a 10 or Ace, and double a hard 9 only against a dealer 3 through 6. You can also double soft hands like Ace-6 or Ace-7 against a weak dealer to press an advantage.
When not to double
Do not double a stiff 12 through 16 - one card can easily bust you, and you are risking more to do it. Some variants let you double on any number of cards or double after splitting, which changes the math. Practice the timing on Classic Blackjack.
Related questions
What is basic strategy in blackjack?
Basic strategy is the mathematically proven best decision for every possible hand you can hold against every card the dealer can show. It was worked out with computer simulations and is usually shown as a color-coded chart. Following it perfectly reduces the house edge to about 0.5%, without any card counting required.
When should you split pairs in blackjack?
The two golden rules are: always split Aces and always split 8s, and never split 10s or 5s. Other pairs depend on the dealer's card - split 2s, 3s, 6s, 7s and 9s mainly when the dealer shows a weak card. Splitting turns a pair into two separate hands, each with its own bet.
Do you hit or stand on 16 in blackjack?
It depends on the dealer's upcard. Stand on a hard 16 when the dealer shows a weak card, 2 through 6, and hit when the dealer shows a strong card, 7 through Ace. If surrender is offered, give up 16 against a dealer 9, 10 or Ace. A pair of 8s that makes 16 should be split, not played as a 16.