To double down in blackjack is to double your stake after the first two cards in exchange for exactly one more card. It is one of the few moments in the game when you add money to a hand with the odds on your side, because it puts extra chips out when the dealer is most likely to lose. The catch is that it works only on a short list of hands, and only on tables that let you use all of them.
On this page
The rule in one line
After seeing your first two cards, you place a second bet equal to the first. You receive one card, face up, and your hand stands automatically. If you win, both bets pay 1:1. If the dealer wins, you lose both.
Written as a sum, for a stake of S:
- result of a double = 2 × S × (outcome of a one-card hand)
- value of doubling = EV(double) − EV(best other play)
The second line is what matters. A double is right only when two bets on a one-card hand beat one bet played freely, with the option to hit again.
When to double down in blackjack
The chart below is for the most common online rule set: six to eight decks, dealer stands on soft 17, double on any first two cards. "D" means double; a blank means hit or stand as the basic strategy chart says.
| Your hand | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | A |
|---|---|---|---|---|---|---|---|---|---|---|
| Hard 9 | D | D | D | D | ||||||
| Hard 10 | D | D | D | D | D | D | D | D | ||
| Hard 11 | D | D | D | D | D | D | D | D | D | |
| Soft 13–14 (A,2 / A,3) | D | D | ||||||||
| Soft 15–16 (A,4 / A,5) | D | D | D | |||||||
| Soft 17–18 (A,6 / A,7) | D | D | D | D |
When the dealer hits soft 17, three cells change: double 11 against an ace, double soft 18 against a 2, and double soft 19 (A,8) against a 6.
Two patterns make the chart easy to hold in your head. Hard doubles spread wide, because 10 and 11 are strong starting points against almost anything. Soft doubles sit in the narrow 3 to 6 window, because a soft hand cannot bust and gains most when the dealer is likely to.
What each double is worth in dollars
These are expected results per $10 initial bet on a six-deck table where the dealer stands on soft 17 and checks for blackjack. A positive number is money you expect to win on average each time the hand comes up. Figures are rounded to the cent.
| Hand | Dealer | Best play without doubling | Double | Gain from doubling |
|---|---|---|---|---|
| 11 (6,5) | 6 | +$3.41 | +$6.83 | +$3.41 |
| 11 (6,5) | 10 | +$1.19 | +$1.78 | +$0.60 |
| 11 (6,5) | A | +$1.48 | +$1.30 | −$0.18 |
| 10 (6,4) | 9 | +$1.17 | +$1.48 | +$0.31 |
| 10 (6,4) | 10 | +$0.27 | −$0.06 | −$0.32 |
| 9 (5,4) | 3 | +$1.08 | +$1.33 | +$0.26 |
| 9 (5,4) | 6 | +$2.07 | +$3.37 | +$1.30 |
| Soft 18 (A,7) | 6 | +$2.80 (stand) | +$3.83 | +$1.02 |
| Soft 18 (A,7) | 3 | +$1.51 (stand) | +$1.79 | +$0.28 |
Three things stand out:
- The dealer's 5 and 6 pay the most. Doubling 11 against a 6 is worth more than three dollars per ten staked over plain hitting. The same 11 against a 10 still gains, but only sixty cents.
- Near the edge of the chart, the gain is small and the mistake is small. Doubling 11 against an ace under these rules costs 18 cents per $10 compared with hitting. Doubling 10 against a 10 costs 32 cents.
- Doubling outside the chart gets expensive fast. A 9 against a dealer 9 is worth −$0.52 if you hit and −$2.97 if you double. That one bad double gives away $2.45 per $10 bet.
The soft 18 rows explain a common habit that costs money. Many players stand on A,7 because 18 "looks finished". Against a 6, standing is worth +$2.80 and doubling +$3.83: standing leaves about a dollar per $10 on the felt.
What doubling restrictions cost
Some tables limit doubles. You can read the limit in the table's info screen next to the payout and soft 17 rule, and it changes the house edge by a known amount. These figures are measured against an eight-deck baseline:
| Table rule | Change to house edge | Doubles you lose |
|---|---|---|
| Double on 9 to 11 only | +0.09 points | every soft double |
| Double on 10 and 11 only | +0.18 points | every soft double, plus hard 9 |
| No double after split | +0.14 points | doubles on hands made by splitting |
| Double on any number of cards (rare, a gain) | −0.24 points | none; you gain extra doubles |
From points to a session
Expected extra cost = hands × stake × points ÷ 100.
| Table | Extra edge | 500 hands at $10 | 500 hands at $50 |
|---|---|---|---|
| 9–11 only | 0.09 | $4.50 | $22.50 |
| 10–11 only | 0.18 | $9.00 | $45.00 |
| No double after split | 0.14 | $7.00 | $35.00 |
| 10–11 only and no double after split | 0.32 | $16.00 | $80.00 |
None of these is as costly as a 6:5 payout, which our 3:2 vs 6:5 page puts at about 1.4 points. But they add up, and a 10–11-only table without double after split adds about two-thirds of the base house edge on top.
Play live and RNG blackjack with crypto.
What moves the value of a double most
- The dealer's upcard. It decides more than your own total. The same hand of 11 gains more than five times as much from a double against a 6 as against a 10.
- Whether the dealer peeks. On no-hole-card tables, a dealer blackjack takes your double too. Hit 11 against a 10 or an ace there instead of doubling.
- The soft 17 rule. An H17 dealer busts more from a soft start, so three extra doubles become correct.
- Partial doubles. Some tables let you double for less. When the chart says double, the full amount earns more; trimming it only trims the gain.
How to double down in blackjack online: a checklist
Before you sit at any table, live or RNG, check the info screen for:
- Which totals can be doubled. "Any two cards" is the line you want to see.
- Double after split. It should say allowed.
- Whether the dealer checks for blackjack. If not, adjust the 11 and 10 rows as above.
- Soft 17. It tells you which version of the doubling chart to use.
- The blackjack payout. A table with every doubling option and a 6:5 payout is still a poor table.
Live studio tables usually show these lines in their rules panel; our live blackjack guide shows where. If you want to see how often a double actually lands, the blackjack odds page has the bust and natural numbers behind it.
Where the double-down blackjack rules are good
The casinos below are the ones we compare on written payout and withdrawal terms. Rules differ table by table inside each lobby, so the checklist above applies at every one of them.
- 1
Vave
4.9/5Casino and sportsbook on one balance, with around 90 coins in the cashier.
Latcas B.V. · since 2022 · Licence Curaçao OGL/2024/1676/0905 · 90 coins: BTC, ETH, USDT, LTC · Sportsbook on the same account
- 2
Bitcasino.io
4.8/5The highest written weekly withdrawal cap we found: 1,000,000 USDT.
EZ Spins Ltd · Licence Anjouan ALSI-202509076 · Withdrawal cap 1,000,000 USDT per week (clause 6.10) · ID check above €2,500 · Sportsbook on the same account
- 3
Wild.io
4.7/5Twelve coins including SOL and USDC, and a weekly cap written as a number.
Stack Gaming Ltd · since 2022 · Licence Anjouan ALSI-202504044-FI2 · 12 coins: BTC, ETH, BCH, LTC · Withdrawal cap $100,000 per week (clause 9.6) · Sportsbook on the same account
- 4
Cafe Casino
4.4/5Twenty-plus blackjack games, Pontoon and Pirate 21 among them, with a crypto cashier.
Arbol Media B.V. · Licence Curaçao OGL/2024/670/0711 · 4 coins: BTC, BCH, ETH, LTC
- 5
Ignition
4.2/5Eighteen RNG blackjack games, from single deck to European, and 48 live blackjack tables.
Arachis Media Ltd · Licence Anjouan
The score counts what each casino publishes about licence, ID checks and limits, not how much we like the lobby.
Questions and answers
What is a double down in blackjack?
You put out a second bet equal to your first, take exactly one more card, and your hand is finished. A win pays even money on both bets.
Should you always double on 11?
Against 2 to 10, yes. Against an ace on a six-deck table where the dealer stands on soft 17, hitting is worth slightly more; if the dealer hits soft 17, double against the ace too.
Can you double down on a soft hand?
On most tables, yes: soft 13 to soft 18 against the dealer's 3 to 6 are the main cases. A table that allows doubles on 9 to 11 only rules all of them out.
Is doubling for less a good idea?
Rarely. When a double is correct, the full double is worth more than a partial one. If the hand is not worth a full double, it is usually not worth a partial one either.
Can I double after splitting?
On most online tables, yes. Where it is not allowed, the table's house edge rises by about 0.14 percentage points.