You hold a hard 15 (no ace counted as 11). The dealer shows a 4. Here is the mathematically correct basic-strategy play — and why.
| Stand ← | -0.2111 |
| Hit | -0.3956 |
| Double | -0.7912 |
| You bust on the next card | 53.8% |
| Dealer 4 busts | 39.4% |
Stand is not close: it beats Hit by 0.1845 per unit. Getting this one wrong costs $1.85 on a $10 bet, every single time. Across the 340 situations in this chart it ranks 268th by expected value — better than 72 of them, worse than 267. 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 4, the dealer ends up busting about 40% of the time. Meanwhile, if you hit hard 15, the next card busts you 54% 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 15 and draw anyway. Over thousands of hands, hitting here costs real money. The chart says stand — every time.