Blackjack is the rare casino game where your decisions change the odds. Play on instinct and the house edge can run high; play the mathematically correct move every time and you can shave it to around half a percent, the lowest of any common casino game. That correct play is “basic strategy”, a complete set of decisions worked out by probability for every hand you can be dealt. This guide explains the strategy, gives you the chart, shows how to read it, and covers the rule variations that change the maths, so you stop guessing and start playing the percentages.
Key takeaways
- Basic strategy is the mathematically best decision for every blackjack hand.
- Played correctly, it cuts the house edge to roughly 0.5%.
- Your move depends on your hand and the dealer’s upcard.
- Always split aces and eights; never split tens or fives.
- Avoid the side bets and insurance, which carry a high house edge.
House edge basics
The house edge in blackjack comes from one rule: you act first, so if you bust, you lose even if the dealer busts afterwards. Basic strategy fights back by making the best statistical choice in every situation, minimising busts and maximising the value of strong hands. It will not turn blackjack into a winning game over the long run, but it brings the edge down to around 0.5% with good rules, far better than the 2% or more a casual player concedes. As covered in our house edge and RTP guide, a lower edge means your money lasts longer.
How to read the chart
Every decision rests on two things: your hand total and the dealer’s upcard (the one card you can see). Find your hand down the side, the dealer’s upcard across the top, and the cell tells you the play. The actions are:
- H = Hit (take another card)
- S = Stand (take no more cards)
- D = Double if allowed, otherwise Hit
- Sp = Split (only for pairs)
The charts below are for the common UK multi-deck game where the dealer stands on soft 17. Exact play varies a little with house rules, so check the table rules before you sit.
Hard totals
A “hard” hand has 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, else Hit | Hit |
| 10 | Double vs 2-6 | Double vs 7-9, else Hit |
| 11 | Double | Double vs 7-10, else Hit vs A |
| 12 | Stand vs 4-6, else Hit | Hit |
| 13-16 | Stand | Hit |
| 17 or more | Stand | Stand |
The pattern to remember: against a dealer’s weak upcard (2 to 6), you stand on stiff totals of 12 to 16 and let the dealer risk busting. Against a strong upcard (7 to ace), you hit those same totals because the dealer is likely to make a good hand.
Soft totals
A “soft” hand contains an ace counted as 11, so it cannot bust on the next card.
| Your hand | Play |
|---|---|
| A,2 / A,3 (soft 13-14) | Double vs 5-6, else Hit |
| A,4 / A,5 (soft 15-16) | Double vs 4-6, else Hit |
| A,6 (soft 17) | Double vs 3-6, else Hit |
| A,7 (soft 18) | Stand vs 2, 7, 8; Double vs 3-6; Hit vs 9, 10, A |
| A,8 / A,9 (soft 19-20) | Stand |
Soft 18 (A,7) is the hand people misplay most. It looks strong, but against a dealer 9, 10 or ace you should hit, because 18 will often lose to those upcards.
Pairs: when to split
| Pair | Play |
|---|---|
| A,A | Always split |
| 8,8 | Always split |
| 9,9 | Split vs 2-9 except 7; Stand vs 7, 10, A |
| 7,7 | Split vs 2-7, else Hit |
| 6,6 | Split vs 2-6, else Hit |
| 3,3 / 2,2 | Split vs 2-7, else Hit |
| 4,4 | Split vs 5-6, else Hit |
| 5,5 | Never split; treat as 10 (Double vs 2-9) |
| 10,10 | Never split; Stand |
Two rules carry the most weight. Always split aces and eights: aces give you two chances at a strong hand, and eights turn a poor 16 into two playable hands. Never split tens (you are breaking up a winning 20) or fives (a 10 is far better doubled than split into two weak hands).
Surrender
Some tables offer surrender, letting you fold a bad hand and reclaim half your stake rather than play it out. Where it is available (usually “late surrender”, offered after the dealer checks for blackjack), basic strategy says to use it on the worst spots:
- Hard 16 against a dealer 9, 10 or ace.
- Hard 15 against a dealer 10.
In those situations, taking back half your stake loses less over time than playing the hand. Surrender is not offered at every table, but when it is, using it correctly trims the house edge a little further.
The rules that change the edge
Not all blackjack tables are equal. A few rule differences move the house edge significantly, so check them before you sit:
| Rule | Effect on the player |
|---|---|
| Blackjack pays 3:2 | Good: the standard, fair payout |
| Blackjack pays 6:5 | Bad: sharply raises the house edge, avoid these tables |
| Dealer stands on soft 17 | Slightly better for the player |
| Dealer hits soft 17 | Slightly worse for the player |
| Double after split allowed | Better for the player |
| Surrender offered | Better for the player |
The single most important one is the blackjack payout. A natural blackjack should pay 3:2 (£15 on a £10 bet). Some tables pay only 6:5 (£12 on a £10 bet), which quietly more than triples the house edge. Always confirm the payout is 3:2 before you play; a 6:5 table is a poor deal however well you play the chart.
Side bets and insurance to avoid
Basic strategy works on the main game. The extras are where the house claws its edge back:
- Insurance: offered when the dealer shows an ace. It is a side bet on the dealer having blackjack and carries a high house edge. Decline it, even with a strong hand.
- Side bets like Perfect Pairs and 21+3: fun, but they carry a much higher edge than the main game. Treat them as entertainment, not strategy.
The low house edge of blackjack lives in the main game only. Every side bet pulls it back up.
What about card counting?
Card counting is the technique of tracking the ratio of high to low cards left in the shoe to bet bigger when the odds favour the player. It is not illegal, but it is not basic strategy, and casinos discourage it and can refuse service to suspected counters. Crucially, it does not work in online play: RNG blackjack shuffles after every hand, and live online tables shuffle frequently and use multiple decks, so there is no persistent count to exploit. For online blackjack, basic strategy is the ceiling of what you can do, and it is genuinely effective. Treat counting as a land-based curiosity, not an online edge.
Bankroll and common mistakes
- Set a session budget and a stake that lets you ride the swings.
- Do not deviate from the chart on a hunch. The maths does not care how you “feel” about a 16.
- Avoid copying the dealer’s “stand on 17” rule blindly; your correct play depends on the dealer’s upcard, not a fixed total.
- Check the payout is 3:2, not 6:5, before you sit.
- Skip insurance every time.
For learning, live tables are ideal because the slower pace gives you time to consult the chart, as our live dealer guide explains. And unlike roulette systems, basic strategy genuinely lowers the edge, because your decisions affect the outcome.
Basic strategy is the closest a casino game comes to a fair fight. Learn the chart, play every hand by the percentages, choose 3:2 tables, and skip the side bets. We list rule-compliant offers on our offers page, and our reviews flag the casinos with the best blackjack rules. Keep stakes sensible, and if gambling stops being fun, our responsible gambling tools can help.
Frequently asked questions
What is blackjack basic strategy?
Basic strategy is the mathematically correct decision for every blackjack hand, based on your total and the dealer’s upcard. Followed consistently, it reduces the house edge to around 0.5%, the lowest of any common casino game.
Should you always split aces and eights?
Yes. Splitting aces gives you two chances at a strong hand, and splitting eights turns a weak 16 into two playable hands. These are two of the most important rules in basic strategy.
What is the difference between 3:2 and 6:5 blackjack?
It is the payout for a natural blackjack. 3:2 pays £15 on a £10 bet, the fair standard; 6:5 pays only £12, which more than triples the house edge. Always choose a 3:2 table, as a 6:5 game is a poor deal however well you play.
Should I ever take insurance in blackjack?
No. Insurance is a side bet on the dealer holding blackjack and carries a high house edge. Basic strategy says to decline it every time, even when you hold a strong hand.
Does card counting work online?
No. Online RNG blackjack shuffles after every hand, and live online tables shuffle frequently with multiple decks, so there is no persistent count to exploit. For online blackjack, correct basic strategy is the most effective approach available.
Does basic strategy guarantee a win?
No. It minimises the house edge but does not eliminate it, so blackjack remains a losing game over the long run. Basic strategy gives your money the best chance to last and reduces avoidable losses from poor decisions.
