Blackjack math
How Often Does the Dealer Bust in Blackjack? The Odds by Upcard
How often does the dealer bust in blackjack? Across a full session, about 28.4% of hands. But that average hides a spread wide enough to drive every stand-or-hit decision in basic strategy, and the entire economics of bust side bets. Behind an ace the dealer breaks one hand in nine; behind a five, more than two in five.
Published Monday, July 6, 2026 · 9 min read
Pick the dealer's upcard. The meter shows the chance the dealer's finished hand goes over 21 (six decks, dealer stands on soft 17).
42.89% dealer bust chance
The worst card in the deck for the house, peak bust frequency.
Dealer bust percentage by upcard: the full table
The blackjack dealer bust percentage is fixed by the drawing rules: the dealer has no choices, so the numbers below are pure combinatorics, not tendencies. This is the six-deck, stand-on-soft-17 table: the same analysis published by Wizard of Odds and every serious blackjack reference since Edward Thorp put dealer outcome tables in print in 1962.
| Dealer upcard | Bust chance | What it means at the table |
|---|---|---|
| 2 | 35.3% | Stiff territory begins, over a third of hands break. |
| 3 | 37.56% | The dealer is drawing to trouble more often than not showing weakness. |
| 4 | 40.28% | Four in ten. This is why basic strategy stands on stiffs here. |
| 5 | 42.89% | The worst card in the deck for the house, peak bust frequency. |
| 6 | 42.08% | The classic "bust card". Marginally safer than a five, despite the folklore. |
| 7 | 25.99% | The cliff: a made 17 is one card away, and busts drop by a sixth. |
| 8 | 23.86% | Pat-hand country. The dealer mostly just makes 18. |
| 9 | 23.34% | Strong upcard; the bust chance is a consolation prize. |
| 10 | 21.43% | Tens make 20s. Standing on a stiff here is basic-strategy suicide. |
| A | 11.65% | The safest card in the shoe for the house, the ace almost never wrecks. |
Two features of this table run the game. First, the cliff between 6 and 7: the dealer bust rate by upcard falls off by sixteen points the moment the dealer can reach 17 with one card. Everything basic strategy tells you about "dealer weak, stand; dealer strong, hit" is that cliff talking. Second, the five-versus-six surprise, the five is the true bust king at 42.89%, despite decades of players calling the six the house's worst card.
The odds behind the meter
The dealer bust rate by upcard is the whole story here. Why does an ace bust only 11.65% of hands while a five busts 42.89%? Because bust requires the dealer to first land in the 12–16 trap and then draw big. An ace counts as 1 or 11, so the dealer's hand flexes around the trap; a five all but guarantees a trip through it. The dealer bust probability is really the probability of being forced through stiff territory with no way to flex out.
The same mechanics decide what the dealer busts with. The most common breaking draw is a ten-value card on a stiff, which is why 22 is the most frequent bust total, a spike big enough that Free Bet Blackjack funds its entire free-double gimmick by declaring dealer 22 a push. And the count of cards in the bust, usually three or four, occasionally a seven-card pileup, is precisely what the Buster Blackjack side bet grades its 2:1-to-250:1 ladder on.
If you play those bust wagers, this page is the fair-value reference: any bet on the dealer breaking is a bet priced against these percentages, with the operator's margin stacked on top. The house edge guide shows exactly how much margin, bet by bet.
How the dealer bust probability moves with the rules
The table above assumes the dealer stands on soft 17. Flip to the hit-soft-17 rule, the American default — and the dealer takes extra draws from the one hand that can't bust on the first hit but can on the second. The overall dealer bust probability creeps up by about half a point, and the ace's bust rate climbs toward 17%, yet the rule still costs players roughly 0.2% of edge, because those extra draws also convert weak 17s into 18s and 19s. More busts is not automatically better for you; it depends on what the surviving hands become.
Deck count nudges the blackjack dealer bust percentage by tenths of a point here and there. Nothing changes the shape: fives and sixes near 42%, the 7-through-ace shelf in the low twenties, the ace at the bottom. Whenever someone at third base asks how often does the dealer bust in blackjack, this table is the whole answer, every strategy chart, every bust wager, every hunch runs on it.