Blackjack basic strategy

Basic strategy is the play with the best expected value for your hand and the dealer’s upcard under a stated set of rules. It is not a way to come out ahead in the long run. Typical games keep a house edge even when you follow the chart. PlayCorrect is educational, for adults 21 and over, and is not gambling advice.

The calculator is the heart of the site: tap the dealer’s upcard, then your cards, and the play appears immediately. This page is the explanation that sits behind those taps.

What “expected value” means here

Each legal action — hit, stand, double, split, or surrender — has an expected value (EV) measured in units of your original bet. A number like −0.535 means that, averaged over every way the unseen cards can fall, that action loses about 53.5 cents per dollar bet. The recommended play is simply the action with the highest EV, even when every option is negative. A “correct” play can still lose the hand in front of you.

PlayCorrect computes those EVs from a finite shoe with the cards of the current hand and the dealer upcard removed, under a US peek (the dealer checks for blackjack with an ace or ten up). The method is described on About accuracy and in the engine notes. We did not copy a published chart into the engine; we computed the table, then checked it.

How to read the chips

Four chips on the calculator (and on the printable card) set the table. Everything else is fixed and listed on rule variations.

• Decks — 1, 2, 6, or 8 (default 6). A few close cells flip when the shoe is thinner. Example: hard 9 vs 2 is a hit in six- and eight-deck S17 (hit EV +0.0772, double +0.0700) and a double in one- and two-deck S17.
• S17 / H17 (default S17). S17 means the dealer stands on a soft 17 (ace-six). H17 means the dealer hits that hand. H17 is slightly less favorable for the player and changes a handful of cells, including 11 vs ace and soft 18 vs 2. See those hand pages.
• DAS on / off (default on). Double after split. When DAS is off, some pair cells — notably 4,4 vs 5 or 6 — stop being splits and are played as the hard total instead.
• Surrender off / late (default off). Late surrender is offered after the dealer has peeked for blackjack. When it is on, some stiff totals against strong upcards become “surrender, otherwise hit.” A pair of eights is usually still a split; see 8s vs ace.

The chips you last used are stored in this browser only (localStorage). Nothing is sent to a server.

How to read a result

• Hit or Stand — take a card, or not.
• Double with a fallback — double the bet and take one card when the table allows it; otherwise hit (code D) or stand (code Ds).
• Split — only on the first two cards, and only for a pair (including two face cards, which count as a pair of tens).
• Surrender with a fallback — only on the first two cards, and only when late surrender is on (Rh means otherwise hit; Rs otherwise stand; Rp otherwise split).

After a third player card, double, split, and surrender are no longer legal. The calculator then recommends only hit or stand. If the two-card chart said “double, otherwise hit,” a later total uses the fallback: hit.

Look at pairs first, then soft hands (an ace counted as 11), then hard totals. A pair of eights is not “a 16.” Two aces are not “a soft 12” until you decide not to split them.

S17 versus H17, in brief

Under our six-deck DAS, no-surrender tables, these are the well-known flips, all of which matched the Wizard of Odds chart on 10 Nov 2026:

• 11 vs ace: hit under S17 (hit EV +0.1473, double +0.1255); double under H17 (double +0.1202, hit +0.1078).
• Soft 18 (A,7) vs 2: stand under S17 (stand +0.1240, double +0.1210); double otherwise stand under H17.
• Soft 19 (A,8) vs 6: stand under S17; double otherwise stand under H17.

DAS and surrender, in brief

DAS matters most for small pairs. With DAS on, six-deck S17 splits 2s vs 2–3, 3s vs 2–3, 4s vs 5–6, and 6s vs 2. Turn DAS off and several of those cells revert to hitting the hard total. Late surrender, when offered, changes hard 16 vs 9, 10, and ace, and hard 15 vs 10, to surrender-otherwise-hit under six-deck S17 — except a pair of eights, which remains a split. Details are on the 16 vs 10 and 15 vs 10 pages.

What this site will not tell you

Exact-card notes use only the cards in your hand and the dealer’s upcard. They are not card counting, not index deviations, and not shoe tracking. Insurance and even money are never taken; the math is on the insurance page. PlayCorrect will not raise the expected value of a typical game above zero. If gambling is a problem, use the help links in the footer.

Do not use a phone or an app to analyze strategy at a casino table. Where the house allows it, a printed card is the usual table aid.