Blackjack Basic Strategy Chart: Lowering the House Edge

A blackjack basic strategy chart is a grid that tells you the mathematically best decision — hit, stand, double down, split or surrender — for every hand you can be dealt against every card the dealer can show. It is not a betting system or a way to beat the house; it is simply the set of plays that loses the least money over time. Played perfectly under common rules, basic strategy trims the house edge to roughly half a percent, which is one of the lowest edges of any game on a casino floor. This guide explains where the chart comes from, how to read it, the full set of decisions for a standard multi-deck game, and the handful of rules that change both the chart and your odds.

What basic strategy is — and what it is not

Basic strategy is the complete list of optimal decisions for a blackjack hand, worked out by computer simulation of millions of rounds. For any combination of your two cards and the dealer’s single face-up card (the “upcard”), there is one play that produces the best long-run result. The chart simply stores all of those answers in one place so you do not have to calculate them at the table.

It helps to be clear about what the chart does and does not do:

• It lowers the house edge; it does not remove it. Even with flawless play the casino keeps a small mathematical advantage. Basic strategy minimises that advantage — it does not flip it in your favour.
• It does not predict the next card. Each decision is based only on the cards already visible, not on what is coming. Unlike card counting, basic strategy requires no memory of past cards.
• It does not change with winning or losing streaks. The correct play for a hand is the same whether you have won or lost the last ten rounds. Chasing losses by betting bigger or deviating from the chart only increases your risk.

If you are still learning the flow of a round — card values, the dealer’s draw rules and when you are allowed to split or double — it is worth reading a plain-language primer on how to play blackjack first, because the chart assumes you already know those mechanics.

What each decision on the chart means

The chart only ever points to one of five moves. If any of these are new to you, this is what they mean in practice:

• Hit — take another card to improve your total. You can keep hitting until you stand or go bust (over 21).
• Stand — take no more cards and let the dealer play. You are betting your current total is good enough.
• Double down — double your original bet in exchange for exactly one more card. You do this on strong starting hands where one extra card is likely to win a bigger pot. Where the chart says “D” but the rules do not allow a double on that hand, you hit instead.
• Split — when you hold a pair, separate the two cards into two hands, each with its own matching bet, and play them one at a time. Splitting aces usually gives you only one card per ace.
• Surrender — give up the hand and reclaim half your bet. This is offered on only the worst hands, such as a hard 16 against a dealer 10. If surrender is not available, the chart’s fallback is to hit.

Every cell in the tables below resolves to one of those moves. The reason the chart can look counter-intuitive is that it always chooses the option that loses the least money on average, which is not always the option that feels safest in the moment.

Where the chart comes from

Basic strategy is not folklore; it has a documented origin. In September 1956 four U.S. Army mathematicians — Roger Baldwin, Wilbert Cantey, Herbert Maisel and James McDermott, later nicknamed the “Four Horsemen of Aberdeen” — published a paper called “The Optimum Strategy in Blackjack” in the Journal of the American Statistical Association. Working on mechanical desk calculators over about 18 months, they produced the first mathematically sound strategy for the game.

Edward Thorp built on their work and popularised it in his 1962 book Beat the Dealer, with the one-deck tables refined by computer analyst Julian Braun. Modern charts are generated by software that can simulate every possible hand exactly, but the result is remarkably close to what the Four Horsemen found by hand seventy years ago. That stability is the point: the correct plays do not change with fashion, so a chart that matches your table’s rules stays valid indefinitely.

How to read a basic strategy chart

Every chart is laid out the same way. The left-hand column lists your hand; the top row lists the dealer’s upcard, from 2 through to an ace. You find the row for your hand, run across to the column for the dealer’s card, and the cell where they meet is your play. The charts below use a 2 through 10 and ace scale for the dealer, where “10” also covers every ten-value card (10, jack, queen and king).

Hands are grouped into three families because they follow different logic:

• Hard totals — hands with no ace, or with an ace that must count as 1 to avoid busting (for example 10-6, a hard 16). These cannot absorb an extra card without risk.
• Soft totals — hands containing an ace counted as 11, such as A-6 (a “soft 17”). Because the ace can drop to 1, you cannot bust by taking one card, so these hands are played more aggressively.
• Pairs — two cards of the same rank, where your first decision is whether to split them into two hands.

Always read the dealer’s upcard first. A dealer showing a 2 through 6 is in a weak position and busts often, which is why you stand on many stiff hands and double more freely. A dealer showing a 7 through ace is strong, so you take more cards to try to reach a competitive total. The charts that follow are for the most common online and land-based game in New Zealand: four to eight decks with the dealer standing on all 17s.

Key: H = hit, S = stand, D = double down (hit if doubling is not allowed), Ds = double down (stand if doubling is not allowed), P = split, P* = split only if doubling after a split is allowed (otherwise follow the hit/stand note), Su = surrender (hit if surrender is not allowed). Never take insurance or even money.

Hard totals

These are your decisions when you hold no ace, or an ace forced to count as 1. The hard 12–16 band is where most money is won or lost, because you stand against a weak dealer and hit against a strong one.

Soft totals

With an ace counted as 11 you cannot bust by drawing one card, so the chart doubles and hits far more than it would on the equivalent hard total. Note that soft 18 (A-7) is not the automatic stand many players assume — it hits against a dealer 9, 10 or ace.

Pairs

Splitting turns one hand into two, each getting a fresh card and a second bet. The two rules worth memorising first: always split aces and eights, and never split tens or fives. A pair of tens is already a 20, and a pair of fives is a strong hard 10 that you would rather double.

The rules that change the chart — and the edge

There is no single “correct” chart, because the best play depends on the exact rules of the table. The variations below each shift the house edge by a measurable amount. The figures are the change versus a standard baseline of eight decks with the dealer standing on soft 17 and doubling after splitting allowed, as published by the independent analyst Wizard of Odds.

Two of these matter far more than the rest:

• Blackjack payout. A natural blackjack should pay 3:2 — $3 for every $2 staked. Tables that pay only 6:5 add about 1.39% to the house edge, which single-handedly undoes everything basic strategy saves you. This is the most expensive rule in the game, and it is worth checking the payout before you sit down or click into a table.
• Dealer hits or stands on soft 17. When the dealer must hit a soft 17 (an ace plus a six), the edge rises by about 0.22%. A table where the dealer stands on all 17s is the better bet, and it also changes a few chart cells — for instance, you double soft 18 and 19 against a six when the dealer hits soft 17.

Fewer decks also help the player slightly: a single-deck game lowers the edge by around 0.48% versus eight decks, all else being equal, though casinos usually offset this with a worse payout or the hit-soft-17 rule. Allowing surrender, re-splitting aces and doubling after a split each shave a little more off the edge in your favour. If you understand how small edges compound over time, the same thinking applies to other games — our guide to Keno odds and the house edge shows how much harder the maths is to beat elsewhere.

Common mistakes the chart corrects

Most losing blackjack habits come from gut feeling rather than the numbers. The chart quietly fixes the expensive ones:

• Standing on a stiff hand against a strong dealer. Players hate hitting 16 and busting, but against a dealer 7 through ace, hitting (or surrendering 16 versus 9, 10 or ace) loses less over time than standing.
• Taking insurance. Insurance is a side bet that the dealer has blackjack. It carries a high house edge of its own and is a losing proposition for a basic-strategy player regardless of your hand. The chart’s advice is simple: never take it, and never accept “even money” on your own blackjack.
• Splitting tens. Breaking up a 20 because two separate hands “feel” like more chances is a classic error. Twenty is already a near-certain winner; keep it.
• Failing to double on soft hands. A-6 against a dealer five is a double, not a timid hit. Skipping these doubles leaves value on the table.
• Mimicking the dealer. Always hitting until 17 ignores the dealer’s upcard entirely and gives back a large chunk of the edge you could have saved.

Using the chart as a New Zealand player

The fastest way to make the chart automatic is to practise in free-play or demo mode before wagering real money — this lets you build the recall without cost, though it does not improve your actual odds, which are fixed by the rules. Most games let you keep a chart open beside the table; there is nothing to hide, as basic strategy is public and used openly.

At New Zealand online casinos you will usually meet four- to eight-deck games, so the charts above apply directly — just confirm the soft-17 rule and the blackjack payout on the table’s info panel first. In live dealer blackjack, where a real dealer streams the cards, the pace is set by the table and you have a fixed window to decide, so having the chart memorised or on hand matters more. The decisions are identical; only the speed changes.

Finally, remember what the chart is for. It makes blackjack one of the lowest-edge games available, but “lowest edge” is not “no edge.” The house still wins over the long run, so treat basic strategy as a way to make your entertainment budget last, not as an income plan.

Responsible gambling

This article is factual information, not betting advice or encouragement to gamble. Basic strategy lowers the mathematical house edge but does not guarantee winning sessions, and no chart, system or amount of practice can turn blackjack into a reliable way to make money — the casino retains an edge on every hand. Gambling is strictly for adults aged 18 or over. Only ever stake money you can afford to lose, set time and deposit limits in advance, and never chase losses by increasing your bets.

If gambling is causing you or someone you know harm in New Zealand, free and confidential help is available from the Gambling Helpline New Zealand on 0800 654 655, any time of day. You can also read our responsible gambling page for tools and support options.

Vanliga frågor (FAQ)

Does a basic strategy chart guarantee I will win at blackjack?

No. The chart gives you the lowest-losing play for every hand, which reduces the house edge to around half a percent under good rules, but the casino still holds an advantage. It improves your long-run results compared with guessing; it does not make blackjack a winning game.

Can I use a strategy chart while playing online or in a casino?

Yes. Basic strategy is public information and is not a form of cheating. Online you can keep the chart open in another window, and many land-based casinos allow a printed card at the table. Only card counting, which tracks the cards still to come, is discouraged by casinos — and basic strategy involves no counting at all.

Why are there different charts for blackjack?

Because the best play depends on the table rules. The number of decks, whether the dealer hits or stands on soft 17, and whether doubling after a split or surrender is allowed all change a few decisions. Use the chart that matches your game; the multi-deck, dealer-stands-on-soft-17 chart above fits most New Zealand online tables.

Should I ever take insurance?

No. Insurance is a separate bet that the dealer has blackjack, and it carries a high house edge of its own. For a basic-strategy player it is a losing bet regardless of what you hold, so the chart tells you to decline it every time, including the “even money” offer on your own blackjack.

What is the single most important rule to check before I play?

The blackjack payout. A table that pays 3:2 on a natural is standard; one that pays only 6:5 adds roughly 1.39% to the house edge and wipes out most of what basic strategy saves you. Always confirm the payout, then check the soft-17 rule, before you commit money.