You're dealt a pair of 7s. The dealer shows a 5. Split or play it as one hand? Basic strategy answers:
| Split ← | +0.1000 |
| Stand | -0.1672 |
| Hit | -0.3214 |
| Double | -0.6428 |
| You bust on the next card | 46.2% |
| Dealer 5 busts | 41.6% |
Split is not close: it beats Stand by 0.2672 per unit. Getting this one wrong costs $2.67 on a $10 bet, every single time. Across the 340 situations in this chart it ranks 136th by expected value — better than 204 of them, worse than 135. 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.
Against a dealer 5 (42% bust chance), splitting 7s turns one mediocre total into two playable hands while the dealer is vulnerable. With double-after-split allowed, you also keep the option to press each new hand — that's where the split profit comes from.