The soft 17 rule determines whether the dealer must hit or stand on a soft 17 hand. It's one of the most important table rules to check before you sit down. It directly affects the house edge and changes a handful of your basic strategy decisions.
A soft hand is any hand containing an ace counted as 11. A soft 17 is specifically an ace plus cards totaling 6, for example, Ace-6, Ace-2-4, or Ace-3-3. The hand is called "soft" because if you draw a card that would bust you, the ace automatically drops from 11 to 1 and you can't bust in one draw.
The opposite is a hard 17, a hand that totals 17 without a flexible ace, like 10-7 or 9-5-3. Hard 17 always stands. The soft 17 rule only concerns the dealer; players can always choose to hit or stand regardless.
Casinos choose one of two rules for the dealer's soft 17:
The dealer must stand when they reach any soft 17. This is better for the player. When the dealer is forced to stop at 17, they have less chance of improving their hand. Blackjack GTO uses S17 rules, which is standard in most Las Vegas casinos.
The dealer must hit when they reach a soft 17. This is worse for the player. Hitting gives the dealer more chances to improve to 18, 19, 20, or 21. H17 adds approximately 0.22% to the house edge compared to S17.
| Rule | House edge (6-deck) | Better for |
|---|---|---|
| Dealer stands S17 | ~0.44% | Player |
| Dealer hits H17 | ~0.66% | Casino |
Assumes 6 decks, double after split, late surrender, blackjack pays 3:2, with perfect basic strategy.
0.22% sounds small but compounded over thousands of hands it's significant. If you're playing 100 hands per hour at $25 a hand, that's $2,500/hour in action. H17 costs you roughly $5.50/hour more than S17. Always look for S17 tables.
If you're playing at an H17 table, a few of your basic strategy plays change versus the standard S17 chart. These are the most important adjustments:
These changes are small in terms of frequency and you won't face them every hand. But playing the wrong strategy for the wrong rule set costs you edge. If you're unsure which rule is in effect, look for a placard on the felt. S17 tables usually say "Dealer must stand on all 17s" and H17 tables say "Dealer must hit soft 17."
The trainer uses S17. Dealer stands on all soft 17s. This is the standard for most Las Vegas Strip casinos and online blackjack with good rules. The full rule set is: 6 decks, S17, blackjack pays 3:2, double on any two cards, split up to 4 hands, late surrender, insurance offered on ace.
Blackjack GTO uses S17 rules and checks every decision against the correct strategy chart. Play as many hands as you want. No money, no sign-up.
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