What Is Dealer Bust Probability in Blackjack?

The single upcard the dealer shows you drives nearly every basic strategy decision — because it drives how likely the dealer is to bust.

Short answer

Dealer bust probability is the chance that the dealer's hand goes over 21 once they finish drawing, given only their visible upcard. It's higher for weak upcards (2 through 6) and lower for strong ones (7 through Ace), because the dealer has no choice about how to play — house rules force the dealer to keep hitting any total under 17, with no option to stand early the way a player can.

Why the dealer can't play like a player

A player can stand on a weak total to avoid busting. A dealer can't — the rules require hitting any hand under 17 (and, at many tables, hitting a soft 17 too). That forced play is exactly why the dealer's upcard is such a strong signal: a dealer showing a 5 or 6 has to keep drawing from a shoe where a large share of the remaining cards are ten-value, which pushes their total past 21 relatively often. A dealer showing a 9, 10, or Ace usually only needs one or two more cards to reach a strong total, so there's much less room for a bust.

How it shapes basic strategy

This single number is the reason the same player total can call for completely different actions depending on the dealer's card. A hard 14, for example, stands against a dealer 6 (their bust risk is high enough that standing lets it work in your favor) but hits against a dealer 9 (their bust risk is low enough that standing usually just hands them the win). Nearly every row of the basic strategy chart reflects this same logic playing out across the dealer's ten possible upcards.

Bust probability vs. final result

Dealer bust probability only describes what happens once the dealer plays out their hand — it's not the same as your win probability, which also depends on your own total and what happens if the dealer doesn't bust. A high dealer bust probability makes standing more attractive on marginal hands, but it doesn't guarantee a win; the dealer still completes a strong hand a meaningful share of the time even against their weakest upcards.

Where the number comes from

Blackjack Decision Lab's probability engine computes dealer bust probability by simulating every possible sequence of cards the dealer could draw under your selected table rules (deck count, and whether the dealer hits or stands on soft 17), not from a fixed lookup table. See How It Works for the full calculation process, or watch the live bust probability update for each hand in the trainer.

See Dealer Bust Probability Live