Double down is an option available to the online blackjack player after he is dealt the first two cards. The option has to be exercised, if desired, before the player hits. Many novice players ignore this option because they have not made the effort to understand double down strategy. Hence they find it convenient to ignore this move. But those online blackjack players who follow this approach are losing out. One of the attractions of online blackjack is that it offers over 99% average return to the player. This return is achievable only if the player doubles down at the right time. Doubling down at the right time greatly increases the probability of winning and this is factored in the average return.

The double down move requires the player to place an additional wager equal to the original one. Thereafter the player will be dealt one card and only one card. Hence it is obvious that the double down option must not be used indiscriminately. Fortunately, the double down strategy is not very difficult to understand and master. The optimum strategy being described below is based on Vegas Strip Blackjack, which is an online blackjack variant that follows the rules prevalent in The Strip in Las Vegas. The double down strategy for other online blackjack variants would be essentially similar, differing in minor details.

Double Down optimum strategy depends on whether the player’s dealt hand is a hard total or a soft total. A soft total contains an ace that can be valued as either 1 or 11 and hence the soft total can have two potential values. The hard total is one that is not a soft total. The double down strategy for hard totals is as follows. The player should never double with hard totals of 12 or more. Four out of thirteen cards in a suit have a value of 10. Hence the probability of being dealt a 10 value card is reasonably high. Doubling down with a hard total of 12 or more is an invitation for busting and losing the doubled stake. Likewise the player should never double down with a hard total of 8 or less. The player will be dealt only one more card and has a high probability of reaching a total that is short of the optimum. Playing without doubling down in this case leaves the player with the option of hitting again, if required.

In the case of hard totals, doubling down is a viable option only for totals of 9, 10 or 11. Here the decision is contingent on the dealer’s face up card. A hand value of 11 is a great candidate for double down. However, if the dealer has an ace he becomes a candidate for blackjack and in this case it is not worth staking the extra amount. A hard total of 10 is a slightly lower position of strength. Therefore double down unless the dealer’s face up card is an ace or a 10 value card. With a hard total of 9, the player should double down unless the dealer’s face up card is two, ace or valued at 7 or more.

With soft totals the player has the cushion of converting the ace to a value of 1 and therefore can be more aggressive on weak dealer hands. The exact rules are as follows. Double down on a soft 17 when the dealer’s face up card is a three, four, five or six. Double down on a soft 15 or 16 when the dealer’s face up card is a four, five or six. Double down on a soft 13 or 14 when the dealer’s face up card is a five or six.