Doubling Down in Blackjack
Doubling down puts up a second bet the size of the first and takes exactly one more card in return. At a six-deck table where the dealer keeps a soft 17 and any first two cards may be doubled, it starts 9.53% of rounds, and those rounds are where the player wins back much of what the house would otherwise keep.
Each doubling hand is priced here against every upcard: the value of the double beside the value of the best play that leaves the stake alone, as the average result per 100 units bet, measured once the dealer has peeked for blackjack. The how-to-play guide explains the button, the full charts are in the basic strategy guide, and pairs have their own splitting page.
Why Doubling Carries the Game
The house holds one structural advantage in blackjack: the player draws first, and a player who busts has lost before the dealer turns a card. Doubling is the main thing the game gives back. It lets the player raise the stake after seeing two cards and the upcard, at exactly the moments the hand is ahead.
The test behind every double is short. The hand is locked to one card, so the double pays when twice the value of the hand after that card beats its value with the freedom to keep drawing. Totals of 9, 10 and 11 pass often, because a single ten-value card lifts them to 19, 20 or 21, and soft hands pass against weak upcards, because one card can never bust them.
Take every double out of the chart and the price of the game climbs from 0.41% to 1.94%. Dropping every split instead adds only 0.57 points.
The key number: A player who never doubles pays 1.53 more points of house edge than one who follows the chart.
What Doubling Gains on Hard 9, 10 and 11
Each cell is the value of doubling minus the value of hitting, in units per 100 bet on the original hand. A positive figure is a double in the chart; a negative one means the hit is worth more.
Hard Doubles, Upcard by Upcard
Hard 11 is the strongest double in the game. Against a dealer 6, doubling earns +67.7 per 100 units bet against +33.8 for a hit, so the extra stake doubles what the hand is worth. The ace is the one upcard where 11 is hit, and only by a hair: the double returns +12.6, the hit +14.7.
Hard 10 is doubled against everything up to a 9. Facing a 10 or an ace the dealer finishes strong too often, and against the 10 the double slips just below zero at ā0.6 while a hit keeps +2.6.
Hard 9 is the narrow one, doubled only against a 3 through a 6. Against a 2 the two plays sit within a unit of each other, +7.0 for the double and +7.7 for the hit; with one or two decks the same hand is doubled, as the single-deck blackjack page explains. Hard 8 is never doubled from a six-deck shoe: even against a 6 its double is worth +9.8 and the hit +12.0.
Passing on these doubles is costly because the hands come up often. A hard 11 turns up once in about 22 hands, and a hit in place of the double forfeits 16.3 per 100 units bet on that hand, or 0.739 points of house edge over the game. Never doubling 10 costs 0.396 points and never doubling 9 costs 0.084; the blackjack tips page ranks these with the other common mistakes.
Soft Doubles From A,2 to A,8
The gain is the value of the double minus the best other play against a dealer 6, in units per 100 bet. Where a soft double is refused, because the hand already has three cards or the table limits doubling, A,7 stands and the smaller soft hands hit.
Why Soft Hands Double Against Weak Cards
A soft hand cannot bust on one card, which takes the main risk out of a double. What it can do is finish low: an A,2 that draws a 4 must stand on a soft 17 it was not allowed to improve. The double therefore pays only against upcards that bust often, while a modest total can still win: the 5 and 6 for every soft hand from A,2 to A,7, the 4 as well from A,4 up, and the 3 for A,6 and A,7. Against a 7 or higher no soft double is right.
Several of these are near ties. As a double, A,2 against a 5 is worth just +0.3 per 100 units bet more than a hit, and A,4 against a 4 just +0.3. A,8 against a 6 falls on the other side: standing on the 19 returns +49.4 and doubling +48.0.
The rule: Double a soft hand only against a weak upcard; against a 7 or anything higher, the plain play is worth more every time.
A soft doubling chance arrives roughly once every 58 rounds. Hitting it instead throws away 6.8 units for each 100 staked on the hand, and a player who never doubles a soft total, from A,2 to A,7 against a 2 through a 6, raises the game's price by 0.118 points. That is far less than the hard doubles cost, since each soft double gains less than a hard one.
Doubling Limits and Their Cost
Every line alters a single rule and leaves the rest of the six-deck game as it is, with the chart refitted. The blackjack odds page lists these among every other rule.
What a Restricted Table Takes Away
A table that doubles only 9, 10 and 11 removes every soft double, which costs 0.10 points. Limiting doubles to 10 and 11 also takes away hard 9 against a 3 through a 6, and the cost nearly doubles, to 0.19. On either table the chart still works: each refused double falls back to its second letter, so D becomes a hit and Ds a stand, and A,7 against a 5 is stood on.
Doubling after a split is a separate line on the rule card. Without it the house edge rises by 0.14 points, mostly because small pairs stop being worth splitting against low cards. Many European tables pair the 9 to 11 limit with no-hole-card dealing, a combination the European blackjack page prices, while Free Bet blackjack turns doubles on hard 9, 10 and 11 into free bets.
Three More Doubles When the Dealer Hits Soft 17
When the dealer must hit soft 17, 3 cells of the chart change and every one becomes a double: 11 against an ace, A,7 against a 2 and A,8 against a 6. Each was a near miss at a table where the dealer stands, with the double trailing by 2.2, 0.3 and 1.4 units per 100 bet in that order.
With the dealer hitting soft 17 the order reverses. Doubling 11 against an ace is then worth +12.0 per 100 units bet to the hit's +10.8; A,7 against a 2 doubles for +11.6 where standing returns +11.3; and A,8 against a 6 doubles for +46.2 where standing returns +45.2. On a table that refuses soft doubles, both soft hands simply stand.
The extra card the dealer draws on soft 17 shifts how those upcards finish just enough to tip each close call. The rule itself, how often it comes up and what it costs, is set out on the soft 17 page.
Doubling Down: FAQs
Some tables allow it, under the name double for less. Where the chart says double, every extra unit staked carries the same favorable expectation, so a smaller double simply collects less of the gain. Where the chart does not say double, no amount is right.
No. Doubling is available only on a hand's opening two cards, including the opening two of a split hand where the table allows it. Once a card has been drawn, the option is gone for that hand.
It is the price of the extra stake. The player raises the bet after seeing the upcard and in return gives up every decision after the next card. That is also why no hard total above 11 appears as a double in the chart: one card leaves a 12 or more stranded too often.
Yes. In a small pack the low cards already in your hand are missing from what remains, so the next card runs high a little more often. One deck adds doubles such as 8 against a 5 or 6, 9 against a 2 and 11 against an ace, and two decks add the last two of those.