Updated 2026-07-22 · 8 decks · S17 · DAS · methodology
Hard 10 vs dealer 9: the verdict
The math is in: double. Against a dealer 9, this hand is strong enough to put double the money on the table.
The numbers
| Action | Win | Push | Lose | EV per $1 |
|---|---|---|---|---|
| Double | 49.3% | 8.7% | 42.0% | +0.144 |
| Hit | 50.1% | 11.4% | 38.5% | +0.117 |
| Stand | 22.8% | 0.0% | 77.2% | −0.543 |
Why double is correct
Doubling wins almost exactly as often as hitting (49.3% vs 50.1%) — the difference is you have twice the money riding on a favorable spot. Against a dealer 9 (bust chance 22.8%), that extra bet is the whole point: EV +0.144 doubled beats +0.117 hit.
For context, a dealer 9 finishes on 17–20 about 71.1% of the time, on 21 6.1%, and busts 22.8%. Those dealer outcomes are the same no matter what you hold — the whole game is choosing the action whose distribution fits them best.
What the mistake costs
Choosing hit instead of double costs about $69 per 100 such hands at $25 a hand (−0.028 EV per dollar). The genuinely expensive error here is stand: −0.687 per dollar, or roughly $1719 per 100 hands at the same stakes.
Does the rule set change it?
No — double holds across every common configuration: Vegas Strip, Atlantic City with late surrender, H17 games and European no-hole-card tables all agree here.
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10 against other dealer cards:
Other key hands vs a dealer 9: