What is a soft 17?
A soft hand contains an ace counted as 11. Ace + 6 is a soft 17: it can also be read as 7, so taking another card can never bust it. A hard 17, like 10 + 7, has no ace counted as 11.
S17 vs H17
Under S17 rules the dealer stands on every 17, soft or hard. Under H17 rules the dealer hits soft 17 and stands on hard 17. Hitting soft 17 helps the dealer: it turns some weak 17s into 18 to 21 without any risk of busting on that card. H17 is generally estimated to add about 0.2 percentage points to the house edge, which is why S17 tables are better for players.
Which decisions change
Only a handful. Against an H17 dealer showing an ace, doubling 11 becomes the better play, and a few soft doubles against weaker dealer cards also gain value. The core of basic strategy stays the same.
How to check
Look at the table felt or the game rules screen: it will say “Dealer stands on all 17s” (S17) or “Dealer hits soft 17” (H17). If you can choose, pick S17.
FAQ
Is S17 or H17 better for the player?
S17. When the dealer stands on soft 17, the house edge is lower.
Is ace + 6 always 17?
It's a soft 17. It can also count as 7, so one more card can't bust it.
Related guides
Strategy and maths reduce the house edge, but never remove it. 18+, play responsibly.