The decision at its simplest
Most of the time, a blackjack decision is a choice between taking another card and keeping what you have. On a hard total, meaning a hand with no ace counted as 11, the choice comes down to a trade-off. Another card might improve the hand, but it might also push the total over 21 and lose the bet immediately. Standing avoids that risk but leaves the hand as it is, to be compared with the dealer’s final total.
What makes the decision interesting is that the right answer for the same player total depends on the dealer’s upcard. You are not just asking whether your hand is good. You are asking how it compares with what the dealer is likely to end up with.
Two probabilities to weigh
The decision rests on two things.
Your chance of busting if you hit. For a hard total of 11 or less, you cannot bust on one card. For 12 and above the risk climbs steadily. Using a simple model of thirteen equally likely values with four ten-valued, a hard 12 busts only on a ten-valued card (4 of 13, about 31 percent), a hard 15 busts on a 7 or higher (7 of 13, about 54 percent), and a hard 20 busts on everything except an ace (12 of 13, about 92 percent). The full set of figures is covered in the discussion of bust probability, so only the key idea is needed here: the risk rises with each step.
The dealer’s chance of busting. The dealer must follow fixed rules, drawing to 16 and standing on 17 or more (with a variation on soft 17 that differs by table). Because of that, the dealer’s upcard largely determines how likely the dealer is to bust. A dealer showing 2 through 6 is relatively weak: the dealer is more likely to start from a total that needs further cards and ends up busting. Roughly speaking, those upcards lead to a dealer bust in somewhere around a third to two-fifths of hands, with a 5 or 6 at the high end. A dealer showing 7 through ace busts much less often, in the range of roughly one hand in six to one in four, and more often finishes with 17 or better. These are approximate and depend on rules and decks. The dealer upcard probabilities for each card are the detailed version.
Putting them together
The weaker the dealer’s card, the less you need to risk. Against a dealer likely to bust, you can let the dealer do the work and stand on a total that would otherwise be uncomfortably low. Against a strong dealer card, standing on a low total is expected to lose, so taking the risk of a hit is often justified.
In outline, the standard chart for hard totals in multi-deck games follows this pattern:
| Your hard total | Against a dealer 2 to 6 | Against a dealer 7 to ace |
|---|---|---|
| 8 or less | Hit (or double on some totals) | Hit |
| 9 to 11 | Hit, or double on 9 to 11 where the chart says so | Hit, or double 10 and 11 against most upcards |
| 12 | Stand against 4 to 6, hit against 2 and 3 | Hit |
| 13 to 16 | Stand | Hit |
| 17 or more | Stand | Stand |
This is a simplified summary. Doubling entries vary with the rules, and a few cells, such as the handling of 16 against a ten or an ace, differ between games. The chart for the game actually being played should be used instead of this outline.
Why the middle rows feel wrong
The part of the table that surprises people is standing on 12 to 16 against a weak dealer card. Standing on a 13 feels timid, since it will lose to many dealer outcomes. The reason it is correct is that the dealer’s upcard is weak enough that busting is a real prospect, while your own bust risk from hitting is worse than the dealer’s. Taking a card would add your bust risk on top of a hand that is already often fine to leave alone.
The mirror image is hitting 12 to 16 against a strong dealer card. Hitting a 14 when the dealer shows a 9 feels reckless, as you are more than 40 percent likely to bust. But standing means you probably lose anyway, because the dealer will often reach 17 to 21 and beat your 14. The hit has a lower expected loss, even though it is not good.
Neither choice is a winning one. Both are ways of picking the smaller expected loss when the position is poor.
A simple illustration
The figures here are rough and for illustration only. Suppose you hold a hard 13 and the dealer shows a 6. If you stand, you win when the dealer busts, which in this spot happens a little over 40 percent of the time. If you hit, you bust on 9 or a ten-valued card (5 of 13, roughly 38 percent) before the dealer plays, and in the remaining cases you often end with a total that still has to beat the dealer. The standing hand keeps the full 40-odd percent chance without adding your own bust risk. The chart’s answer for this spot is to stand, but it is an average judgement, and any one hand can go either way.
Limits of the idea
Three points keep the lesson in proportion.
First, a hit or stand decision does not make your hand more likely to win in some absolute sense. It selects the better of two imperfect choices.
Second, a single result says very little about whether the decision was right. Standing on a 13 and watching the dealer make 20 does not mean standing was wrong.
Third, the cards that came before do not change the probabilities of the next draw in the way many people expect. A run of tens does not make a small card “due”, which is the gamblers fallacy, and the chart’s answers do not depend on it.
The chart reduces what the game costs on average. The casino still keeps an edge, so play only with money you can afford to lose and take a break if you notice you are chasing losses. If gambling feels out of control, a local support service can help.