Blackjack Strategy Calculator
Enter your two cards and the card the dealer is showing. You get the right play straight away — hit, stand, double, split or surrender — solved for the exact rules of the table you are at, not read off a generic chart.
This calculator needs JavaScript — it solves the hand rather than looking it up, so the work happens in your browser. The short version for the most common game (6 decks, dealer stands on soft 17, double after split allowed): hit hard 16 against a dealer 7 or higher, stand on it against 2 through 6, always split aces and eights, never split tens or fives, and double 11 against everything except an ace.
Why this gives different answers to the chart in your pocket
Basic strategy is not one chart. It moves with the number of decks, with whether the dealer hits soft 17, with whether you are allowed to double after splitting, and with whether surrender is on the table. Most printed charts pick the most common rule set and leave it at that, which is fine until you sit down at a game that differs — and the game in front of you usually does.
This tool does not store a chart at all. Every cell, every recommendation and every edge figure above is solved when you change a control: it removes your two cards and the dealer’s upcard from the shoe, computes the dealer’s full distribution of final totals, then values standing, hitting, doubling, splitting and surrendering against it and returns whichever is worth most. Change a rule and the whole grid is recomputed from scratch.
How to read the expected values
Each action is priced per unit staked. A stand worth −22% means that over many identical hands you would lose 22 cents of every dollar bet — which is still the right play if hitting loses 28 cents. Blackjack has a lot of hands like that. Hard 16 against a ten is the famous one: every option is bad, and the whole skill is in picking the least bad, which is why the tool tells you the margin as well as the answer.
When the margin is under one percent of a bet, the decision is close enough that it barely matters — the tool says so rather than pretending the chart is gospel. When it is several percent, the difference is real money and worth memorising.
What the rules are actually worth
The panel at the bottom re-solves every opening hand with each rule flipped, so the figures next to the toggles are what that rule is worth to you rather than a number copied from somewhere. The one that should stop you is the blackjack payout: a table paying 6:5 instead of 3:2 costs you around 1.4% — more than every other rule on the board combined, and more than the entire house edge of a good game. No amount of correct play recovers it.
The model, and where it stops
Two simplifications are worth knowing about. The solver removes the three cards you can see but does not deplete the shoe further as a hand plays out, which is the standard way strategy charts are generated and makes it a basic-strategy engine rather than a card counter — it is a touch optimistic on single deck as a result. And it values a split as two hands rather than modelling resplits to three or four, which is slightly pessimistic on pair-heavy rule sets. Neither changes which action the chart recommends; both move the absolute edge figure by a few hundredths of a percent. The differences between rule sets, which is what the bottom panel is for, are unaffected.