usefulweb.appDependable little tools for people and AI agents. Blackjack Basic Strategy Calculator
Theme: Auto

Theme

Apps Part of Playcards

Blackjack Basic Strategy Calculator

Blackjack basic strategy chart and expected values computed for your table rules.

More options

Ranks 2–10, J, Q, K, A separated by a comma.

☁ Sign in to save to your Google Drive

Try an example: 6 decks, dealer stands on soft 17, double after split · Soft 18 against a 3 (6 decks, H17) · Pair of eights against a 10, single deck

More about this tool

How it works

Computes the blackjack basic strategy for the rules at your table — number of decks, dealer hits or stands on soft 17, double after split, late surrender, which totals may double, 3:2 or 6:5 — from the exact dealer probabilities of the shoe, not from a copied chart. Enter a hand and the dealer’s up card to see the expected value of hit, stand, double, split and surrender. Play money and learning only: basic strategy lowers the house edge but never beats it.

  • The dealer’s final totals (17–21 or bust) are computed exactly by recursion over the shoe with your two cards and the up card removed, conditioned on the dealer not having blackjack (US peek rule: with an Ace or ten-value up card the dealer checks first, so you only lose your original bet to a blackjack).
  • Hit, stand and double are valued with your extra cards drawn from the shoe with removal; a split hand is valued as a hand starting from one card (doubling only with double after split, split Aces get one card each, no re-splitting). Each hard total is averaged over its two-card combinations weighted by probability (total-dependent strategy).
  • The house edge sums every starting hand and up card with its probability, pays 3:2 or 6:5 for a natural, and assumes this strategy with no insurance. It is an estimate: re-splitting and composition-dependent plays are not modelled, so published figures can differ by about 0.05 %.

For learning and play money. No strategy removes the casino’s edge; gambling with real money can be addictive.

Sources

Part of Playcards

  • Playcards Card games table

    Mau-Mau, Schlafmütze, Blackjack, Skat and Doppelkopf vs the computer, at home or online.

    Open Playcards

Related tools

How to use the Blackjack basic strategy calculator

Get the basic-strategy table and estimated house edge for your table rules, or the best move and expected values for one hand.

What it is for

Basic strategy is the best decision for every Blackjack hand when you only know your own cards and the dealer's up card. Printed charts are made for one set of rules; change the number of decks or let the dealer hit soft 17, and some cells change. This calculator works the strategy out for the rules you enter — decks, soft 17, doubling, double after split, late surrender and the blackjack payout — and estimates the house edge.

Enter two cards and a dealer card and it also shows the expected value of every action for that hand. It does not count cards, and it is meant for understanding the game and for play-money tables such as Playcards — not as betting advice.

Worked example

The default example is the common shoe game: 6 decks, dealer stands on soft 17, double after split, blackjack 3:2. The tool estimates the house edge at 0.46 % and prints three tables: Hard totals, Soft totals and Pairs. Hard 12 hits against 2 and 3 and stands against 4 to 6; 11 doubles against everything except an Ace.

Switch on Dealer hits soft 17 and enter A,7 against a 3. The edge rises to 0.67 %, and the summary says A,7 against 3: Double, else stand. The table Your hand A 7 against 3 shows why: stand +0.1416, hit +0.0881, double +0.1748 per unit bet. Under hit-soft-17 rules A,8 now doubles against a 6, and 11 doubles against an Ace.

For a single deck game, no double after split, 8,8 against 10 still says Split — at −0.4651 per unit it is the least bad choice, ahead of hit (−0.51) and stand (−0.5183). Change the payout to 6:5 and the single-deck edge jumps from about 0 % to 1.26 %: the payout costs far more than any strategy cell.

How to read the result

  • House edge (estimate): what the casino keeps on average per unit bet when you play this strategy perfectly. Negative means a slight player advantage.
  • Hard totals, Soft totals, Pairs: rows are your hand, columns the dealer's up card. H hit, S stand, D double (else hit), Ds double (else stand), P split, R surrender (else hit).
  • Your hand … against …: the expected value of each action for the hand you entered; the highest one is the advice.

Tips and common mistakes

  • Enter the rules of your table first; one changed rule can flip several cells.
  • “Double, else stand” matters when doubling is not allowed (three cards, or a restricted double rule).
  • Never take insurance without counting cards; it costs more than it returns.
  • Avoid 6:5 tables: no strategy makes up for the lower payout.
  • Expected values near zero mean the choice barely matters; large gaps are the decisions worth learning.

FAQ

Why does the house edge differ slightly from published charts?

The calculator works out the dealer's outcomes exactly but evaluates a split as one split only, without re-splitting. Published figures that include re-splits are a few hundredths of a percent lower.

Is basic strategy the same as card counting?

No. Basic strategy ignores the cards already played; counting adjusts bets and some decisions to them.

Does the Playcards app use this strategy?

Yes. The hint under your hand in Playcards' Blackjack comes from the same computation, for the house rules of your table.

Guide last updated:

For scripts and AI agents

  • JSON API: POST https://playcardsblackjackstrategy.usefulweb.app/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://playcardsblackjackstrategy.usefulweb.app/mcp · tool name playcards_blackjack_strategy
Example request
curl -s -X POST https://playcardsblackjackstrategy.usefulweb.app/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{"decks":"6","h17":false,"das":true}'
Feedback · ideas & bug reports welcome