Blackjack : Use Double Down in Blackjack to reduce the House Edge

Doubling down in blackjack, means making an extra bet equal to or less than the original bet after you have seen the dealer’s faced up card. After wagering, you will be able to take only one card.

This bet is useful when both your and the dealer’s cards give you an edge, and when you expect to make more money than if you would have stand or hit. Because this bet requires extra money, many players avoid placing it especially when the dealer makes hand after hand, or when they have a limited budget.

Because of this they will make many mistakes like hitting when they have 7-2 against the dealer’s 4, or standing when they have Ace-7 against the dealer’s 3.

Usually when someone doesn’t double down he doesn’t take the chance of reducing the edge, but that has a benefit though: by not doubling down he could win the bet and avoid losing a double one.

For example if the player hits when he has 5-6 against the dealer's 9, and he receives a card from 6 to 10, and then stands he has the same chances of winning than if he would have doubled down.

If the card would be an ace through five he would have the chance to hit again, thus improving his winning chances. In the case of a double down he wouldn't be able to do this.

Still people like to take risks and they double down even when they shouldn't. Sometimes they get lucky and win even when the odds were clearly against them. There are cases when the player has won by doubling down on 10-8 against the dealer 10. He was dealt a 3 and the dealer received a 10; but these cases are very rare.

Doubling down has risks no matter the situation. When you have a low starting hand, you could remain vulnerable, or when you have a high starting hand you could bust. When you are between, you can hope for a draw.

Many players double down when they have ace-two or ace-three against dealer three or four, ace-four or ace-five against dealer three, and ace-two through ace-seven against dealer two, because these hands are considered soft. The problem in this situation is that the player can make a strong hand with only one extra card and most of the times that does not happen.

In an eight-deck game with no re-splitting, when a basic strategy is used, the house has 0.59% advantage, which could be considered a fair game.

The advantage is increased to 1.37% if the player doesn’t double down once in a while. Of the 1.37 percent, doubling down on 11 represents 0.74%, on 10 represents 0.46%, on nine represents 0.08% and on soft hands represents 0.09%.

As you can see doubling down can reduce the house edge a lot. If you are uncertain about doubling down, start doubling down on nine or soft 13 through 18, because you will only forfeit 0.08 and 0.095.