Blackjack has one of the lowest house edges in the casino — under 0.5% when you play by basic strategy. That beats roulette (2.7%) and most slots (4–10%). This guide explains every decision: when to hit, stand, double, split or surrender.
What is basic strategy?
Basic strategy is the mathematically optimal play for every possible hand combination in blackjack. It was derived in the 1950s by four US Army engineers using early computers, and later validated by Edward Thorp in Beat the Dealer. Casinos cannot ban you for using it — it's perfectly legal.
Basic strategy assumes a standard 6-deck game, dealer stands on soft 17, and double-after-split is allowed. Minor rule variations shift the edge by 0.1–0.2%.
Hard hand rules
| Your Hand | Dealer 2–6 (weak) | Dealer 7–Ace (strong) |
|---|---|---|
| 8 or less | Hit | Hit |
| 9 | Double (vs 3–6), else Hit | Hit |
| 10 | Double | Double vs 2–9, Hit vs 10/Ace |
| 11 | Double | Double vs 2–10, Hit vs Ace |
| 12 | Stand vs 4–6, Hit otherwise | Hit |
| 13–16 | Stand | Hit |
| 17+ | Stand | Stand |
Soft hand rules (hand contains an Ace counted as 11)
| Your Hand | Dealer 2–6 | Dealer 7–Ace |
|---|---|---|
| Soft 13–14 (A2, A3) | Double vs 5–6, else Hit | Hit |
| Soft 15–16 (A4, A5) | Double vs 4–6, else Hit | Hit |
| Soft 17 (A6) | Double vs 3–6, else Hit | Hit |
| Soft 18 (A7) | Double vs 3–6, Stand vs 2/7/8, Hit vs 9/10/Ace | Stand vs 7–8, Hit vs 9/10/Ace |
| Soft 19–20 (A8, A9) | Stand | Stand |
Splitting pairs
| Pair | Rule |
|---|---|
| Aces | Always split. Two chances at 21. |
| Eights | Always split. 16 is the worst hand; splitting gives two fresh 18s. |
| Tens / Face cards | Never split. 20 is near-unbeatable; don't break it. |
| Fives | Never split. Treat as 10 and double instead. |
| Fours | Only split vs dealer 5–6; otherwise hit. |
| Twos & Threes | Split vs dealer 2–7, else hit. |
| Sixes | Split vs dealer 2–6, else hit. |
| Sevens | Split vs dealer 2–7, else hit. |
| Nines | Split vs dealer 2–6 and 8–9; stand vs 7/10/Ace. |
When to double down
Doubling down lets you place an extra bet equal to your original and receive exactly one more card. It's most powerful when you have a strong total and the dealer is showing a weak card (2–6). The most common doubles are:
- 11 vs dealer 2–10 — nearly always profitable
- 10 vs dealer 2–9
- 9 vs dealer 3–6
- Soft 16–18 vs dealer 3–6
Insurance — never take it
Insurance pays 2:1 if the dealer has blackjack, but the true odds are closer to 9:4 against. Even card counters rarely take insurance. Over time it always costs money — skip it every time.
House edge by strategy level
| How you play | Approx. house edge |
|---|---|
| Perfect basic strategy | ~0.5% |
| Good intuitive play | ~2% |
| Guessing / hunches | 4–6% |
Blackjack at crypto casinos
Crypto casinos like Stake, BC.Game and Cloudbet offer multiple RNG blackjack variants with lower minimum bets than traditional casinos. Some offer live dealer blackjack with professional dealers streamed in real time. Bitcoin and USDT deposits are instant and usually free.
Look for European blackjack (dealer doesn't peek — slightly lower house edge) or Classic Blackjack with 3:2 payout on naturals rather than 6:5.