Basic strategy is the mathematically best way to play every blackjack hand, based only on your two cards and the dealer’s up card. It doesn’t beat the house, but it brings the house edge down to roughly half a percent under common rules, far lower than most casino games. The whole strategy fits on a few tables, and most of it comes down to a handful of rules you can learn in an evening.
The tables below are for the most common online and casino rules: four to eight decks, the dealer stands on soft 17, and you can double after splitting. If the dealer hits soft 17 or other rules differ, a few borderline plays change, but everything here stays close to correct.
The rules that cover most hands
Stand on hard 17 or more. Always split aces and eights. Never split tens or fives. Double on 11 against anything except an ace, and on 10 against anything up to 9. With 12 to 16, stand against a dealer 2 to 6 and hit against 7 or higher, except 12, where you also hit against a 2 or 3. Never take insurance.
That last one matters more than it sounds. Insurance is a side bet that the dealer has blackjack, and it loses money over time unless you’re counting cards.
Hard totals (no ace, or an ace counted as 1)
| Your hand | Dealer 2–6 | Dealer 7–A |
|---|---|---|
| 8 or less | Hit | Hit |
| 9 | Double vs 3–6, hit vs 2 | Hit |
| 10 | Double | Double vs 7–9, hit vs 10 and A |
| 11 | Double | Double vs 7–10, hit vs A |
| 12 | Hit vs 2–3, stand vs 4–6 | Hit |
| 13–16 | Stand | Hit |
| 17+ | Stand | Stand |
Soft totals (an ace counted as 11)
| Your hand | Dealer 2 | Dealer 3–4 | Dealer 5–6 | Dealer 7–8 | Dealer 9–A |
|---|---|---|---|---|---|
| A,2 or A,3 | Hit | Hit | Double | Hit | Hit |
| A,4 or A,5 | Hit | Double vs 4, hit vs 3 | Double | Hit | Hit |
| A,6 | Hit | Double | Double | Hit | Hit |
| A,7 | Stand | Double | Double | Stand | Hit |
| A,8 or A,9 | Stand | Stand | Stand | Stand | Stand |
Where the table says double but your casino won’t let you, hit instead, except with A,7, where you stand.
Pairs
| Your pair | What to do |
|---|---|
| A,A | Always split |
| 10,10 | Never split; stand |
| 9,9 | Split vs 2–6 and 8–9; stand vs 7, 10 and A |
| 8,8 | Always split |
| 7,7 | Split vs 2–7, otherwise hit |
| 6,6 | Split vs 2–6, otherwise hit |
| 5,5 | Never split; play as a hard 10 |
| 4,4 | Split vs 5–6, otherwise hit |
| 2,2 or 3,3 | Split vs 2–7, otherwise hit |
Why it works
Every decision in basic strategy is the play with the best long-run result for that exact situation, worked out by simulating millions of hands. The dealer has to follow fixed rules, so when their up card is weak (2 to 6), they’re likely to bust and you can afford to stand on a low total. When their card is strong (7 to ace), standing on 12 to 16 usually loses, so you take the risk of hitting.
Rules that change the odds more than strategy
Check the payout for blackjack before you sit down. A table that pays 3:2 gives you $15 for a $10 blackjack; one that pays 6:5 gives you $12, which adds roughly 1.4 percentage points to the house edge, more than every rule in this guide saves you. Fewer decks and a dealer who stands on soft 17 also help the player. Our guide to RTP and house edge explains how small percentages add up over a session, and if you also play roulette, this guide covers its bets and payouts.
18+. Basic strategy reduces the house edge; it doesn’t remove it. Set a budget and gamble responsibly.