Regardless of whether blackjack is played online or in a land-based casino doubling down is a highly advantageous play to make. The key is knowing when to double down and why those times are the best to do so.

First the double down play is a blackjack play in which the player doubles his or her original bet and receives only one more card before standing. Because only one more card is received it is important to already have a good starting hand total.

Doubling down, per basic strategy, should be done when dealt the following hard hands against the specified dealer up cards:

- Hard 9 vs. dealer’s 3-6
- Hard 10 vs. dealer’s 2-9
- Hard 11 vs. dealer’s 2-10

The reason it is most advantageous to double down on these hands is because, statistically speaking, this hands have good potential of becoming strong hands with one card. And even if the blackjack player receives a low card and their hard hand becomes a stiff hand, the dealer still has a decent shot of busting—which is what is desired when faced with a stiff hand.

Doubling down allows a blackjack player to earn double their payout if they win. It is taking full advantage of being dealt a good starting hand total.

If you had bet $10 and been dealt one of the above hands, would you rather be paid $10 for winning or $20?

If a blackjack player is in the position to take full advantage of their hand and make the more on a payout, then he or she should. And that is the point of doubling down in blackjack.

Many novice blackjack players do not always know what to do when they are dealt a pair. Should they play it as a hard hand or split it?

While a basic strategy chart can easily tell a player which way to play a pair, sometimes it helps to understand why a particular play should be made.

There are some pairs that you do not split. In those cases it is more advantageous to play them as a hard hand. A pair of 5’s is such a pair.

The reason that you do not want to split this pair is that its total as a hard hand is 10. And hard 10’s are advantageous to double down on. They are also half of 21. And while you cannot receive a 3-2 payout for a three card 21, it will still beat everything the dealer has unless he has a natural blackjack.

But the main reason not to split a pair of 5’s is because of its double down potential.

In a $10 game in which you split a pair of fives you have $20 on the line on two separate hands. If you win both hands you would be paid $40. But if you only won one hand you would be paid $20 on that hand and lose the other $10, breaking even in effect.

And it would be difficult to hit a 5 and build another good hand, let alone two good hands.

But if you were to keep the pair together and doubled down, yes, you would still have $20 on the line, but if you won you would be paid $40 without the worry of breaking even that is found in pair splitting.

This is why it is more advantageous to keep the two 5’s together and double down on them. You have a greater potential to win a larger amount. And that is the point of strategy, to find the best way to win the most and hang on to the money you already have.

In blackjack there come points in time during the game when the player can go on the offensive—when their hand is stronger than the dealer’s. But how do you know when to go on the offensive? When you are dealt a starting total of 9, 10 or 11 is when you take your blackjack strategy to the offensive side.

The best play to make when you find your starting hand total to be one of those three is to double down. Doubling down sends a message to the dealer that you are confident and that your hand is strong—that you have a better chance of out-drawing the dealer and that you are going to do so with one card.

Granted, we not always win when we double down, but it is a fun play to make.

Doubling down is when you double your original bet and only receive one more card. Many players are a bit intimidated by only receiving one more card, but when you consider that you are already starting with a 10 or 11, you already have half of what you need to total 21. And if you are starting with 9 you are already halfway to having 20—another strong hand.

And by having the potential of creating a strong hand and winning with that hand, you have the chance of doubling your winnings since your bet was doubled.

Having a starting total of 11 is the strongest of the three. It offers you the most opportunities to double down. If you have a starting total of 11 and the dealer’s up card is a 2 through 10, double down. The only time you do not double down is when the dealer’s up card is an Ace.

In regards to having a starting total of 10, you will want to double down when the dealer’s up card is a 2 through 9.

And when you have a starting total of 9, you need to double down when the dealer’s up card is a 3 through 6.