Blackjack: the rules, the chart, and the honest math

How a hand actually plays

You are not playing against anyone at the table. It is you against the dealer’s hand, and the goal is a higher total without going over 21. Cards 2–10 count face value, face cards count 10, and an ace counts 11 or 1, whichever helps.

1. You bet, then everyone gets two cards. Yours face up; the dealer shows one and hides one.
2. You act first. Hit (take a card), stand (stay), double (one more card for double the bet), or split a pair into two hands. Go over 21 and you lose immediately, before the dealer does anything.
3. The dealer has no decisions. They reveal the hole card and must draw to at least 17, then stop. No reads, no mood, just a fixed script printed on the felt.
4. Closest to 21 wins. Even money on a normal win; an ace-plus-ten two-card 21 is a “blackjack” and should pay 3:2.

That dealer script is the whole reason a correct play exists for every situation. Since the dealer’s behaviour is fixed, the math of every decision was solved decades ago. You do not need to memorise reasoning at the table. You need the chart.

How to read it

Find your hand on the left, the dealer’s up-card along the top, and do what the cell says. Three patterns carry most of the chart: stand on 12–16 only when the dealer shows a bust card (mostly 2–6, with 12 standing only against 4–6); double your 10s and 11s when your start beats theirs; and never bust a soft hand (the ace lets you draw aggressively).

Two rules are worth knowing cold because they feel wrong at the table: always split aces and eights (sixteen is a disaster; two eights are not), and never split tens. Twenty already wins.

What basic strategy does, and what it cannot do

The chart shrinks the house edge to about 0.5%. It does not flip it. Over a long night the casino still expects to keep 50 cents of every $100 you put through a 3:2 table; the chart’s job is to stop that being $2. Card counting, the one technique that historically pushed the edge negative, does not survive online play: RNG tables shuffle every hand and live studios cut the shoe deep.

The table rules that change the number

Two tables that look identical can cost you very different money, and online lobbies mix them freely:

• 3:2 vs 6:5 blackjack. A $10 blackjack pays $15 at a 3:2 table and $12 at a 6:5 table. That one line in the rules adds roughly 1.4% to the edge, nearly quadrupling it against a basic-strategy player. Check the table info before you sit; it is always published.
• Insurance. Offered whenever the dealer shows an ace, and priced at roughly a 7.4% edge in a multi-deck game. “Even money” on your own blackjack is the same wager in a costume. The chart answer is never.
• Side bets. Perfect Pairs and 21+3 run edges from 3% to past 10% depending on the paytable. They get their own honest page.

What players get wrong

From the thousands of player discussions behind our research, the same three leaks come up: taking insurance “to protect a good hand”, standing soft 18 against a 9 or 10, and abandoning the chart after a bad run because the table feels cold. The cards have no memory. The chart is correct on the next hand whatever happened on the last five. That is what an edge of 0.5% instead of 2% buys you.