Blackjack Guides: Rules & Basic Strategy
Blackjack is the casino game where your decisions matter most. Our blackjack guides teach you the rules, the basic strategy that cuts the house edge to around 0.5%, and the table rules that make a game worth playing – or worth avoiding.
Blackjack Rules in Brief
You play against the dealer, not other players. The goal is to finish with a hand closer to 21 than the dealer's without going over.
- Card values: 2–10 count at face value, jacks, queens and kings count 10, and aces count 1 or 11.
- Blackjack: an ace plus a 10-value card as your first two cards. It usually pays 3:2.
- Your options: hit (take a card), stand, double down (double your bet and take one card), split (play a pair as two hands) and sometimes surrender (give up half your bet).
- The dealer draws until reaching 17 or more, following fixed rules.
Basic Strategy Essentials
Basic strategy is the mathematically best play for every combination of your hand and the dealer's upcard. These are the most important rules for a typical multi-deck game where the dealer stands on soft 17:
| Your hand | Dealer shows | Best play |
|---|---|---|
| Hard 8 or less | Any | Hit |
| Hard 9 | 3–6 | Double, otherwise hit |
| Hard 10 | 2–9 | Double, otherwise hit |
| Hard 11 | 2–10 | Double (also against an ace in many games) |
| Hard 12 | 4–6 | Stand, otherwise hit |
| Hard 13–16 | 2–6 | Stand, otherwise hit |
| Hard 17+ | Any | Stand |
| Soft 13–14 (A-2, A-3) | 5–6 | Double, otherwise hit |
| Soft 15–16 (A-4, A-5) | 4–6 | Double, otherwise hit |
| Soft 17 (A-6) | 3–6 | Double, otherwise hit |
| Soft 18 (A-7) | 2–6 / 7–8 / 9–A | Double (stand vs 2) / stand / hit |
| Pair of aces or 8s | Any | Always split |
| Pair of 10s | Any | Never split – stand |
| Pair of 5s | 2–9 | Treat as hard 10 – double |
Exact plays vary slightly with the number of decks and table rules. Our blackjack winner's guide covers the full strategy.
Rules That Change the House Edge
| Rule | Effect for the player |
|---|---|
| Blackjack pays 6:5 instead of 3:2 | Bad – adds roughly 1.4% to the house edge |
| Dealer hits soft 17 | Bad – adds about 0.2% |
| Fewer decks | Good – single and double-deck games are better |
| Double after split allowed | Good |
| Late surrender available | Good |
| Double only on 9–11 or 10–11 | Bad |
The single most important check: only play tables where blackjack pays 3:2.
Should You Take Insurance?
When the dealer shows an ace, you are offered insurance – a side bet that the dealer has blackjack, paying 2:1. In multi-deck games the house edge on insurance is high (around 7%), so basic strategy says never take it. "Even money" when you have blackjack is the same bet in disguise.
Card Counting and Online Blackjack
Card counting is legal in land-based casinos, although casinos can refuse to let you play. Online RNG blackjack reshuffles the cards after every hand, so counting does not work. Live dealer games use shoes that are cut deep and reshuffled early, which makes counting impractical.
Popular Blackjack Variants
- Classic / European blackjack – the standard game.
- Blackjack Switch – swap cards between two hands, but blackjack pays 1:1.
- Free Bet Blackjack – free doubles and splits on some hands; the dealer pushes on 22.
- Spanish 21 – played without 10s, with generous player bonuses.
- Live blackjack – real dealers and tables; see our live dealer guides.
Find a table with good rules at our top online blackjack casinos.
Blackjack Mistakes to Avoid
- Standing on 12–16 against a strong dealer card (7 to ace) – basic strategy says hit.
- Not doubling on 11 against a dealer 10 or lower.
- Splitting 10s – a hard 20 is a winning hand; keep it.
- Taking insurance or even money.
- Playing 6:5 tables.
- Chasing losses by raising your stakes after a losing streak.
Blackjack Bankroll Management
Blackjack has swings, even with perfect strategy. A common rule of thumb is to bring at least 20–40 times your average bet for a session, so a few bad hands don't end your game early. Splits and doubles mean you may need to place extra chips on some hands, so keep some of your bankroll in reserve.
Side Bets
Popular side bets such as Perfect Pairs, 21+3 and Bust It offer big payouts but usually carry a much higher house edge than the main game. Treat them as occasional fun and keep your stakes small.
Basic strategy is the mathematically optimal decision for every possible hand against each dealer upcard. Following it reduces the house edge to around 0.5% in a good game.
Yes. Basic strategy says to always split aces and 8s, whatever the dealer shows.
No. Insurance has a high house edge in multi-deck games, so basic strategy players never take it.
No. RNG blackjack reshuffles after every hand, and live games reshuffle early, so counting gives no real advantage online.
At 3:2, a £10 bet pays £15 for a blackjack; at 6:5 it pays just £12. The 6:5 rule adds roughly 1.4% to the house edge.
A common guideline is 20–40 times your average bet, so you can absorb normal swings and still make doubles and splits.