Blackjack Basic Strategy
The math of the one casino game where your decisions move the edge
Blackjack is the casino table game where your own play changes the house edge most. Played with perfect basic strategy on a good table, the house keeps about 0.43% of what you bet. Played by feel, it keeps several times that.
The house edge depends on the rules
The 0.43% figure is for a common eight-deck game: the dealer stands on soft 17, you can double on any first two cards and after splitting, split to four hands, no surrender, and blackjack pays 3:2. Every rule change moves it. The biggest is the payout on a blackjack: a table that pays 6:5 instead of 3:2 costs you roughly 1.39 percentage points, more than all the other rule changes combined. Walk past 6:5 tables.
Basic strategy, the core of it
- Hard 12: stand against a dealer 4, 5 or 6; hit against everything else.
- Hard 13 to 16: stand against a dealer 2 through 6; hit against 7 through ace.
- Hard 17 or more: always stand.
- Doubles: double 11 against a dealer 2 through 10, and 10 against a dealer 2 through 9.
- Splits: always split aces and eights. Never split tens or fives.
- Insurance: never take it, unless you are counting cards and the count says so.
The full chart covers every soft hand and pair against every dealer card, and it shifts slightly with the number of decks and whether the dealer hits soft 17. The printable cards below carry the exact chart for shoe, double-deck and single-deck games.
Counting cards with Hi-Lo
Card counting is legal, but casinos can refuse your play. Hi-Lo is the standard count: add 1 for each 2 through 6 you see, subtract 1 for each 10, face card or ace, and count 7, 8 and 9 as zero. Divide the running count by the decks left to get the true count. The higher the true count, the more tens and aces remain, and the more the game tilts toward you. A count also changes some basic-strategy plays, like taking insurance.
Practice it free
The free blackjack simulator deals real shoes and trains basic strategy and the Hi-Lo count, all in your browser.
Go further
Carry the strategy to the table on a printable strategy card, or get every number worked out in The Complete Blackjack Strategist.
More free guides
All six games are in the free casino simulators.
Gambling carries real risk of loss, and no strategy removes the house edge on these games. Play only where it is legal and you are of age. If gambling stops being fun, call 1-800-GAMBLER. See the disclaimer.