Enter an original two-card hand, the dealer upcard and a supported rule profile. The result comes from versioned basic-strategy tables—there is no AI call, personal opinion or bet-size advice.
Strategy engine v1.0.0
Get one checkable decision
Conventional American peek/hole-card blackjack only.
Basic-strategy decision
Example result
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Select the cards and rules.
Applicable strategy-chart row
The marked cell matches the selected dealer upcard. Codes include the fallback where applicable.
| Hand | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | A |
|---|
H = Hit · S = Stand · D/H = Double; otherwise Hit · D/S = Double; otherwise Stand · P = Split · R/H, R/S or R/P = Surrender; otherwise the shown action
Supported game family
Version 1.0 supports conventional blackjack with a dealer hole card and an American peek before player action, dealer upcards 2 through Ace, 3:2 blackjack, doubling on any original two cards, and total-dependent hard, soft and pair strategy. Deck profiles are single deck, double deck and 4–8 decks; S17/H17 and DAS/no-DAS are supported throughout.
Late surrender is supported only for 4–8 decks, either against every upcard or against 2–10 only. Single- and double-deck surrender profiles are intentionally excluded because the checked source pages conflict on a fine-point pair exception. The engine stops rather than guesses.
Unsupported rules and variants
- Early surrender and surrender before a dealer blackjack check.
- European no-hole-card or no-peek games.
- Restricted doubling such as 9–11 or 10–11 only.
- Subsequent/multi-card hands, split-limit state and count-based deviations.
- Spanish 21, Free Bet Blackjack, Super Fun 21, Blackjack Switch, Double Exposure, push-22 games, side bets and other nonstandard variants.
Read the game’s posted rules before choosing a profile. The Blackjack Rule-Comparison Tool explains how selected rule differences affect the game; it cannot identify the rules of the table you are using. For the full teaching context and chart notation, read the basic-strategy guide.
Decision order and fallbacks
The engine checks a supported late-surrender cell first, then an exact-rank pair, then a soft total, then a hard total. A pair means the same rank: K+K uses the pair row, while K+Q is an equal-value hard 20, not a pair. Double codes carry a hit-or-stand fallback. Split fallback is calculated by reclassifying the same cards without the pair action. Surrender codes carry their exact hit, stand or split fallback.
A worked example: soft 17 against a dealer 6
Select A and 6 for your original cards, dealer 6, 4–8 decks, S17 and DAS. Under the supported American-peek rules with doubling on any first two cards, the result is Double; otherwise Hit. The ace counts as 11, so this is soft 17. Standing simply because the total is 17 misses the distinction between a soft hand and a hard hand.
With an initial $10 wager, doubling adds $10: $20 is now at risk, and you receive exactly one additional card. If that card is a 10, the ace changes to a value of 1 and your final total is hard 17. The fallback tells you how to play when the double action is unavailable; it is not a claim that hitting and doubling have identical expected value.
Keep the inputs tied to the original two-card decision. After hitting, do not enter two cards that merely reproduce your new total: that can incorrectly reopen doubling, splitting or surrender. For subsequent decisions, use the full strategy chart and the actions actually available. If the game restricts doubling to 9–11, it falls outside this tool’s supported rules even though the result displays a fallback.
Sources checked 30 August 2026
- Wizard of Odds basic-strategy calculator, by Michael Shackleford: complete visible total-dependent matrices for deck group, S17/H17, DAS/no-DAS, surrender and American peek settings.
- Wizard of Odds surrender analysis: late-versus-early surrender definitions and deck-dependent fine points.
These recommendations draw on the linked mathematical research. Match every listed assumption before applying a result: a chart for a different game can give the wrong decision even when your cards look the same. An unsupported-rule warning means you need a chart specifically suited to that game.