Players may have the option to double down, or just double, after receiving their first two cards and seeing the dealer’s up-card, but before taking any additional cards. Doubling involves matching the original bet by stacking the same amount in chips behind the original bet. Some casinos allow players to “double for less” by adding a lesser amount than the original bet. When doubling, players get exactly one additional card and cannot take more regardless of the impact of that card.
Many casinos (or specific blackjackBlackjack, also referred to as 21, is a popular casino card game where players attempt to have a hand value closer to 21 than the... More tables in the casino) have distinct rules for which two-card hands players are allowed to double (often limiting players to totals of 10 or 11, or 9, 10, and 11).
Doubling down is often advantageous to the player depending on the two-card combination and the dealer’s up-card. While totals of 9, 10, and 11 are the most obvious two-card hands for doubling (since there are four-times as many 10-value cards as any other card in the deck), there are other hands where doubling has a positive impact on expected value (a variety of soft hands, since the ace can take two values depending on what is best for the player; see the basic strategyBasic Strategy The basic strategy, or just basic, is the best way to play each hand without keeping track of cards removed from play during... for details). As such, casino rules that limit doubling to hard totals of 9, 10, or 11 increase the casino’s expected returnExpected value or EV is the average return one can expect to get from a repeated decision, such as from a gamble, if it is... and decrease the appeal of the game for players who know the basic strategy.