You hold a hard 20 (no ace counted as 11). The dealer shows a Ace. Here is the mathematically correct basic-strategy play — and why.
| Stand ← | +0.6555 |
| Hit | -0.8521 |
| Double | -1.7043 |
| You bust on the next card | 92.3% |
| Dealer Ace busts | 16.7% |
Stand is not close: it beats Hit by 1.5076 per unit. Getting this one wrong costs $15.08 on a $10 bet, every single time. Across the 340 situations in this chart it ranks 21st by expected value — better than 319 of them, worse than 20. Expected value is per unit staked, computed for multi-deck, dealer stands on soft 17, double after split allowed. The model and the code are published as data.
Showing a Ace, the dealer ends up busting about 12% of the time. Meanwhile, if you hit hard 20, the next card busts you 92% of the time. When the dealer is this likely to destroy their own hand, taking that risk is a losing trade — you stand and let the math work against them.
This is one of the most common mistakes at the table: players feel 'weak' standing on 20 and draw anyway. Over thousands of hands, hitting here costs real money. The chart says stand — every time.