Dealer bust probability by upcard
The short version: with 6 decks and the dealer standing on soft 17, the dealer busts about 42% of the time with a 5 or 6, 40% with a 4, 35–37% with a 2 or 3, 23–26% with a 7 through 10 and 17% with an ace (excluding dealer blackjacks). On average, the dealer busts on 29.1% of the hands where they don’t have blackjack.
Dealer stands on soft 17 (S17)
| Upcard | Bust | 17 | 18 | 19 | 20 | 21 | Has blackjack |
|---|---|---|---|---|---|---|---|
| 2 | 35.4% | 14.0% | 13.5% | 13.0% | 12.4% | 11.8% | — |
| 3 | 37.4% | 13.5% | 13.0% | 12.5% | 12.1% | 11.5% | — |
| 4 | 39.6% | 13.0% | 12.4% | 12.1% | 11.7% | 11.2% | — |
| 5 | 41.8% | 12.2% | 12.2% | 11.8% | 11.2% | 10.8% | — |
| 6 | 42.3% | 16.6% | 10.6% | 10.6% | 10.2% | 9.7% | — |
| 7 | 26.2% | 36.9% | 13.8% | 7.9% | 7.9% | 7.4% | — |
| 8 | 24.4% | 12.9% | 36.0% | 12.9% | 6.9% | 6.9% | — |
| 9 | 22.9% | 12.1% | 11.7% | 35.2% | 12.0% | 6.1% | — |
| 10 | 23.0% | 12.1% | 12.1% | 12.1% | 36.9% | 3.8% | 7.7% |
| Ace | 16.6% | 18.8% | 18.9% | 18.9% | 18.9% | 7.8% | 30.9% |
Dealer hits soft 17 (H17)
| Upcard | Bust | 17 | 18 | 19 | 20 | 21 | Has blackjack |
|---|---|---|---|---|---|---|---|
| 2 | 35.7% | 13.0% | 13.6% | 13.1% | 12.6% | 12.0% | — |
| 3 | 37.7% | 12.6% | 13.2% | 12.7% | 12.2% | 11.6% | — |
| 4 | 39.9% | 12.2% | 12.6% | 12.2% | 11.8% | 11.3% | — |
| 5 | 42.0% | 11.8% | 12.3% | 11.8% | 11.2% | 10.9% | — |
| 6 | 43.9% | 11.5% | 11.5% | 11.5% | 11.0% | 10.6% | — |
| 7 | 26.2% | 36.9% | 13.8% | 7.9% | 7.9% | 7.4% | — |
| 8 | 24.4% | 12.9% | 36.0% | 12.9% | 6.9% | 6.9% | — |
| 9 | 22.9% | 12.1% | 11.7% | 35.2% | 12.0% | 6.1% | — |
| 10 | 23.0% | 12.1% | 12.1% | 12.1% | 36.9% | 3.8% | 7.7% |
| Ace | 20.1% | 8.3% | 20.7% | 20.7% | 20.7% | 9.6% | 30.9% |
How to read it and how it was calculated
- The “Bust” and 17–21 columns add up to 100% and are the probabilities once dealer blackjack has been ruled out, which is the situation you’re in when you decide at a table with a hole card. The last column is the chance of a dealer blackjack before the peek.
- Exact calculation (not simulation) with the Veintiuno engine: 6 decks, the dealer’s upcard is removed and every possible card is played out. We checked it against an independent simulation of 1.5 million hands per upcard, with differences of a few tenths of a point.
- With fewer decks, or once the players’ cards are taken into account, the numbers shift slightly, but the order never changes.
What to do with this table
It’s the whole reason basic strategy looks the way it does. With 12 through 16 against a 4, 5 or 6 you stand, because the dealer busts close to half the time they don’t already have 17–21; against a 7 or higher you hit, because they’ll almost always end up on 17 or more. The most debated case is explained in 16 vs 10.
Frequently asked questions
Which upcard makes the dealer bust the most?
A 6 or a 5: around 42% of the time when the dealer stands on soft 17. With a 4, close to 40%. That’s why you stand on 12 through 16 against a 4, 5 or 6.
Which upcard makes the dealer bust the least?
An ace: once blackjack has been ruled out, the dealer busts about 17% of the time. With a 7, 8, 9 or 10, between 23% and 26%.
How much does it change if the dealer hits soft 17 (H17)?
The dealer busts a bit more with low cards and with an ace, because they keep hitting in spots where they used to stand; but they also finish on 18–21 more often. Overall, H17 is worse for the player: it raises the house edge by about 0.2 percentage points.