Get the dealer bust and outcome probabilities by upcard and the correct basic-strategy action (hit, stand, double, split) for your hand — pure math, no wagering.
Describe your hand and the dealer's upcard. Action follows multi-deck basic strategy (S17, double-after-split).
About this tool
The Blackjack Odds & Basic-Strategy Calculator computes the dealer's outcome probabilities for any upcard and tells you the mathematically correct play for your hand. Choose the dealer's upcard (2 through Ace) and describe your hand as a hard total, a soft total, or a pair, and it returns the recommended action plus the full dealer distribution — all computed live in your browser with no betting involved.
The dealer probabilities come from an exact recursion over an infinite (uniformly shuffled) shoe: the dealer draws until reaching 17 or more, and the tool tracks every path to a final total of 17, 18, 19, 20, 21, or a bust. Toggle whether the dealer stands or hits on soft 17 (S17/H17) and whether the dealer peeks for blackjack — with peek on, a natural is conditioned out of an Ace or ten upcard. The dealer's bust probability ranges from roughly 12–17% on an Ace up to about 42% on a 6, which is why a 5 or 6 upcard is the player's friend.
The recommended action reads from a standard multi-deck basic-strategy table (dealer stands on soft 17, double-after-split allowed) covering hard totals, soft totals, and pairs. For hard totals the tool also shows your own bust-on-hit probability — for example a hard 16 busts on any card 6 through King, or 8 of 13 ranks ≈ 61.5%. Under typical rules, following basic strategy holds the house edge to around 0.5%.
Frequently asked questions
How are the dealer probabilities computed?
By exact recursion on an infinite deck: each rank is drawn with its true frequency (four ten-value cards, one of every other rank), the dealer hits below 17, and every branch is summed into final totals of 17–21 or bust. It is deterministic math, not a simulation or live data.
What is the difference between S17 and H17?
S17 means the dealer stands on all 17s including a soft 17 (Ace + 6); H17 means the dealer hits soft 17. Hitting soft 17 slightly raises the dealer's chance of reaching 18–21, which is worse for the player and adds roughly 0.2% to the house edge.
Why does my hand bust probability matter?
It is the chance that taking one more card puts a hard total over 21 — the count of ranks that would bust divided by 13. A hard 12 busts only on a ten-value card (about 31%), while a hard 16 busts on 6 through King (about 61.5%), which is why stiff hands are so dangerous to hit.
Does the strategy account for surrender or insurance?
No. The action table covers hit, stand, double, and split for hard hands, soft hands, and pairs under multi-deck S17 with double-after-split. Late surrender and the insurance side bet are not included, and insurance is a losing bet under basic strategy anyway.