How to double up in blackjack

Double Down - When to Double Your Blackjack Bet

Double down is the technical term for that in blackjack Double the stake with a promising starting hand. In the following article I will explain all the important points about “Double Down”.

How does a double down work?

Double down is the third most common choice in blackjack, along with hit (draw a card) and stand (stand). There are casinos that allow you to double your bet on any starting hand. In English this is called “double down on any two cards”. If you want to use the double-down option, you have to place a bet in the amount of the original bet in the betting field when it is your turn. There is also the option “Double for less”, with which you can also bring less than the basic stake. However, this variant is very rare.

For example, if you have wagered $ 10 and have a good starting hand, you place a second bet of $ 10 next to the first bet. In doing so, you risk 20 euros in the hope that the third card will give you a high total score. When you double up, you say to the dealer "Double down". The acoustic cue of doubling is particularly important when you have a pair so that the dealer doesn't mistakenly suspect that you want to split the pair - even though you would have to point at the cards with your forefinger and middle finger spread. With the addition “Double Down” you are on the safe side. If you have decided to double up, you only get one more card and thus have a total of three cards. If this result is higher than the dealer's or if the dealer overbids himself with more than 21, then you win 20 euros on top of your stakes

When should you double the stake?

In the blackjack strategy table you can see the mathematically correct decision for every possible situation at the blackjack table. For situations in which you should double down, a D is an abbreviation for double down. Since you only get one more card when you double up, you should only double up hands that you cannot overbought with. So card combinations under 12, so that one would not have a losing 22 with a ten-valued card.

Double down with 9, 10 and 11

According to the optimal blackjack strategy, you should

double on starting hands with the values ​​9, 10 and 11.

However, it plays Dealer-Up Card - the dealer's open card - a crucial role:

  • You only double with 9 against a 3, 4, 5 or 6 from the dealer.
  • A 10 is doubled against a dealer up card of 9 or lower
  • With 11 you double against any dealer up card

Double down with soft hands

If the rule “Double Down on any two cards” applies in the casino, this means that you can not only double 9, 10 and 11, but also any other card combination. You should only use this for further card combinations with an ace - the so-called soft hands.

This rule is the standard. Rarely does a casino prohibit the doubling of soft hands. For example, it is not allowed in Casino Fuerteventura.

If doubling with a soft hand is allowed, you should do so in the following situations:

  • A7: against any dealer up card from 3 to 6
  • A6: against any dealer up card from 3 to 6
  • A5: against 4, 5 and 6 of the dealer
  • A4: against 4,5 and 6 of the dealer
  • A3: against 5 and 6 of the dealer
  • A2: against 5 and 6 of the dealer
  • A8 and A9: never
  • A10 = blackjack

Ace +8 (19) and Ace + 9 (20) are too strong hands so don't risk doubling down on them. With an ace and a 10, a jack, a queen or a king you have made blackjack and already won at a ratio of 3: 2, so that you cannot double at all, even if you would like to have some irrational reasons.

Double down when counting cards

When counting cards, you follow the cards played and draw conclusions about the cards that are still in the deck of cards. Using a card counting system, if many high cards have been previously played, you know that there is less chance of another high card. In this case, card counters deviate from the stipulations of the blackjack strategy table and do not double against a high dealer card.

Don't be afraid to double up!

I keep seeing players in casinos who skip good doubling situations. Either because they don't know that you can double up at all, because they don't know that you should double up, or even because they are afraid of losing twice. If you only ever risk the minimum stake and are afraid of doubling down, you are probably playing in a league that is too high and should play with lower stakes.

The bankroll plays a role in this. Because you can still double up after splitting a couple if you find one of the above-mentioned constellations. You can split a maximum of four hands and double each of them. The maximum bet in such a - admittedly very rare - case is eight times the basic bet.

So you should always keep in mind that you may have to bet more to get the best out of it and win the most. If you don't do that, you are leaving your money behind and making the casino even richer.

By foregoing doubling in good situations, you also forego statistical profit. Of course you can also lose when you double, but in most cases it is worth doing as described above.

Take over duplication from others

I am happy to offer cowardly blackjack players to pay their double in attractive situations. In this way I buy myself an advantageous situation in which I, for example, win 70% of the time. While the players, who don't double up themselves, leave behind money, I regularly collect money without much effort.

For example, if a player has a 10 or 11 against a dealer card under 10 and does not want to double himself, I offer him that I double for him if I get the doubling profit. In order for this to work, you should always have a little chat and make friends with the players. You first have to prove to many that you know what you are doing so that they allow you to intervene in their game.

When you double up, you only get one more card. This can of course also be bad. In 30% of the cases you lose a doubling, so in one out of three cases. It can then happen that you are accused of having destroyed the coward's game by doubling up, since he could have taken another card himself if he had not doubled. In such a case, I like to pay the lost stake to show that I am opposed to criticism and that I am sure that I will make a profit in the long run.


If you are not very familiar with gambling, you might get the idea to double your stake after a loss. The principle behind it is called “Martingale”. You double your stake with every defeat. If you then won, you would have recovered the loss.


Maybe you do well a few times, but sooner or later you lose several times in a row. The problem with blackjack and in the casino in general: There are table limits. Of course, casinos have known for hundreds of years that theoretically with an endless bankroll it would be possible to win with the Martingale strategy.

As a rule, the strategy fails because of the player's capital.

Assuming you start with 10 euros, the doubling steps after defeats would be the following:

10 – 20 – 40 – 80 – 160 – 320 – 640 – 1280 – 2560

That's only 9 levels. With 8 defeats in a row you would have to bet 2560 euros to make up for the whole loss and win a total of 10 euros. An insane calculation. And 8 defeats in a row are absolutely nothing special! That happens to just about every player every night. If it doesn't happen, it's luck. If it happens, it's not bad luck, just a normal probability.

However, it can also be the case that you lose 26 times in a row and, according to the law of large numbers, it even out in 1,000 or 10,000 games and approaches the expected probability. We also take a short trip to Monte Carlo in 1913.

Incredible streak at Roulette in Monte Carlo 1913

The legendary Monte Carlo story is appropriate to illustrate the occurrence of series in gambling. Maybe that's why the number 13 has its origin as an unlucky number, because this story happened in 1913!

In the casino in Monte Carlo, the upper class played roulette. The ball landed on black 26 times in a row! That must have been some kind of world record. Nevertheless, there is a huge difference between losing 8, 10 or even 15 times in a row, which is absolutely realistic, to blacking 26 times.

On that day, the casino in Monte Carlo made one of the biggest wins in its history. All the players in the casino got wind of this incredible series. After 15 blacks, more and more players are betting more and more money on red! Because of course: at some point there has to be black again!

That's true too. But whether the next attempt will be the same at some point, or whether - as in this case - the same color will appear 11 more times, is in the stars.

The mistake of reasoning that inexperienced players keep making is a wrong idea of ​​probability. Just because you've lost X times in a row doesn't mean you are entitled to a fateful victory.

The probability is always the same before each round of roulette: 18 out of 37 cases are red. Black occurs in 18 out of 37 cases.

This corresponds to a probability of 48.64% each. Adding up, this gives the probability of 97.28 that either red or black will appear. In 2.72% of all games, however, the ball lands on 0 and both red and black lose.

Compare: If you bet on a color, wins in

51.36% the casino 100% of your stake.

In just

48.64% you gain 100% of your stake.

This disproportion is called the house edge. And you can't get around the house edge with betting systems like the Martingale system.

Therefore, you should never double the stake after a loss or a win. The wager in blackjack depends on the order in which the cards are played. But this is something for advanced card counting users.

The Double down option but you should always use it if you encounter one of the above situations!

Gambling Expert, Journalist & Video Producer
2007: Discovered passion for blackjack on first trip to Vegas.
2010: The only editorial German blackjack website set up.
2007 - today: Blackjack play in casinos around the world
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Categories Blackjack Blog, Blackjack RulesTags Blackjack Rules, Double Down, Option, Double Up