A soft hand is one holding an ace counted as eleven, so it cannot bust with one more card: ace-six is a soft 17, and drawing a five makes it a hard 12 rather than a bust. The phrase matters mostly because of what the dealer is obliged to do with one.
Every blackjack table prints its instruction on the felt. S17 means the dealer stands on all 17s. H17 means the dealer hits soft 17. The player has no choice in the matter either way; the rule is the house's, and it is the second thing to read after the payout line.
H17 costs the player 0.22 percentage points against an otherwise identical S17 game.
That sounds small next to a 6:5 payout, which costs 1.35 percentage points, and it is. It is not small next to the game itself: a standard rule set costs about 0.52%, so moving from S17 to H17 raises the cost of playing by roughly two fifths.
The reason a dealer hitting soft 17 hurts you is not that the dealer busts less often. The dealer busts slightly more often. It is that the hands the dealer draws to are better on average than the 17 being abandoned, and 17 is a weak total that loses to everything above it. Trading a weak certainty for a distribution with more 18s, 19s, 20s and 21s in it is good for the dealer even at the cost of extra busts.
Two smaller consequences follow. Doubling and splitting decisions against a dealer ace shift under H17, and surrender, where it is offered, becomes slightly more valuable. Both are second-order next to simply choosing the S17 table when both are open.
Where the numbers come from
Related terms in casino floor
- House edge, The average share of each bet the casino expects to keep over the long run.
- Natural, A hand that wins immediately on the first cards dealt.
- Insurance, The side bet offered when the dealer shows an ace. Every source calls it a bad bet; this one gives the figure, and it changes with the number of decks.
- Expected value, The average result of a bet if it could be repeated indefinitely.
Where an entry quotes a number, that figure comes from the computed sections of this site rather than from another glossary, so the definition and the derivation cannot drift apart. Each entry links to the page where the number is worked out.