When to double down in blackjack
Updated 15 October 2026 · Rules referenced: six decks, dealer stands on soft 17, blackjack pays 3 to 2
Doubling down is the one move in blackjack that lets you raise your bet in the middle of a hand, after you've seen your cards and the dealer's upcard. Used in the right spots, it's where a basic-strategy player earns back much of the house edge.
This guide explains exactly when to double under this site's rules: six decks, dealer stands on soft 17, doubling allowed on any first two cards and after a split.
What doubling down means
After your first two cards, you can double your bet. You put in a second stake equal to the first and receive exactly one more card, then your hand is over. You can't hit again, however low the total.
That trade sums up doubling. You get twice the money on the hand, but you give up control. So doubling only makes sense when one card is very likely to leave you in good shape, and when the dealer is likely to be in trouble.
The doubling chart for hard hands
| Your hand | Double against | Otherwise |
|---|---|---|
| Hard 11 | 2 to 10 | Hit against an ace |
| Hard 10 | 2 to 9 | Hit against 10 and ace |
| Hard 9 | 3 to 6 | Hit |
| Hard 8 or less | Never | Hit |
| Hard 12 or more | Never | Follow the hit/stand chart |
Eleven: double against everything but an ace
Eleven is the best doubling hand in the game. Any ten-value card, nearly a third of the shoe, gives you 21. A 7, 8 or 9 gives you 18 to 20. Nothing can bust you. Double it against every dealer card from 2 to 10.
The one exception is a dealer ace. With six decks and a dealer who stands on soft 17, hitting 11 against an ace is very slightly better than doubling, because the dealer finishes strong so often. The margin is tiny, and in games where the dealer hits soft 17 the answer flips to double. That's a good example of why charts are tied to specific rules.
The only hands you'd rather have are blackjack and 20. So when you see a 6 and a 5, or a 7 and a 4, the decision should be automatic.
Ten: double against 2 through 9
Ten works the same way as eleven but is slightly weaker: a ten-card gives you 20 rather than 21. Against a dealer 10 or ace, that small difference matters. The dealer is likely to finish on 19 to 21, and a single card leaves you exposed, so you should just hit and keep the option to draw again.
Nine: double against 3 through 6
Nine is borderline. One ten-card makes 19, which is good, but many cards leave you on a weak total of 12 to 16 with no chance to improve. It's only worth doubling when the dealer is at their weakest, showing 3, 4, 5 or 6, because then even a mediocre total often wins when the dealer busts. Against a 2 the dealer is just a little stronger, so you hit instead.
Soft doubles
Soft hands (an ace counted as 11) can't bust on one card, which makes them good doubling hands against a weak dealer:
- Ace-2 and ace-3: double against 5 and 6.
- Ace-4 and ace-5: double against 4, 5 and 6.
- Ace-6: double against 3, 4, 5 and 6.
- Ace-7: double against 3, 4, 5 and 6. If you can't double, stand.
Most players never double a soft hand, which leaves value on the table. The soft hands guide explains each one.
Doubling after a split
At this table you can double on the first two cards of a hand created by a split, except split aces, which only receive one card. This rule changes more than you might expect. A split 4 that catches a 7 becomes an 11 you can double, and it's the reason fours are split against 5 and 6.
After a split, play each new hand exactly as if it had been dealt to you that way. If a split 8 receives a 3, you have 11, so double it.
When you can't double
You can only double on your first two cards. If you've already hit, the option is gone. In that case:
- Where the chart says double on a hard hand, hit instead.
- Where the chart says double on soft 18, stand instead. Soft 18 is the only exception.
Common doubling mistakes
- Doubling hard 12 or more. These hands bust too easily on one card. Doubling multiplies a bad situation.
- Doubling ten against a ten. It feels like ten matches ten, but the dealer is more likely to finish strong, and you'd want the option to hit again.
- Doubling nine against a 2 or a 7. Nine is only strong enough to double when the dealer is at their weakest, showing 3 to 6.
- Skipping soft doubles. Ace-6 against a 4 is a double. Players who stand there or just hit are giving up value.
- Doubling to chase losses. Doubling is a strategy decision based on the cards in front of you, not a way to win back what you've lost. The session so far has no effect on the next card.
Why doubling matters so much
The house edge comes from the fact that you act first. If you bust, you lose even if the dealer busts afterwards. Doubling is one of the few tools that pushes back. You add money only in spots where you're the favourite. Together with the 3-to-2 blackjack payout and splitting, it's how basic strategy brings the house edge down to around half a percent. Read the house edge explained to see how the numbers fit together.