Blackjack rewards decisions more than any other common casino game. Play every hand by basic strategy at a table with good rules, and the house edge on a multi-deck game is roughly 0.3% to 0.6%. Play by feel, or sit at a table that pays 6:5 on blackjack, and the edge rises fast: the 6:5 rule alone adds about 1.39 percentage points. This guide covers where the game came from, how basic strategy and card counting were discovered, how strategy changes with the table rules, and ten practical tips for choosing and playing an online table. For the rules, a basic strategy chart and demo play, start with our free blackjack hub.
The history of blackjack
From veintiuna and vingt-et-un
Card games where players aim for a total of 21 are centuries old. Miguel de Cervantes described one, veintiuna, in his story Rinconete y Cortadillo, published in 1613 in his Exemplary Novels: his two card sharps cheat at it. In 18th-century France vingt-et-un (“twenty-one”) was a fashionable game, and it travelled to North America with French settlers.
The American game
American gambling halls in the 19th and early 20th centuries played twenty-one with house rules that varied widely. A popular story says some halls paid a bonus for an ace of spades with a black jack (the jack of spades or clubs), and the name “blackjack” stuck even after the bonus disappeared. When Nevada legalised casino gambling in 1931, blackjack became one of its core table games.
The maths arrives: 1956 and 1962
In 1956 four US Army engineers, Roger Baldwin, Wilbert Cantey, Herbert Maisel and James McDermott, published “The Optimum Strategy in Blackjack” in the Journal of the American Statistical Association. Using desk calculators, they worked out close to the correct play for every hand: the first basic strategy. Mathematician Edward Thorp refined it on an IBM computer and showed that tracking the cards already played could give the player an edge. His book Beat the Dealer (1962) became a bestseller, and casinos responded with more decks, earlier reshuffles and barring of counters.
Online and live blackjack
RNG blackjack arrived with the first online casinos in the mid-1990s. Because the software can reshuffle before every hand, card counting has no effect. Live dealer blackjack, streamed from studios since the 2000s, brought real cards and shoes back, along with large-format tables where unlimited players share one dealer hand. Our guide to live dealer casinos explains the technology.
Why basic strategy works
The house edge in blackjack comes from one rule: if you bust, you lose, even if the dealer busts afterwards. The player gets three things back in return: a 3:2 payout on blackjack, the option to double and split, and the freedom to stand on any total, while the dealer must draw to 17. Basic strategy uses those options in the best possible way for every hand against every dealer up card.
A big part of the logic is how often the dealer busts, which depends heavily on the up card. Weak up cards force the dealer to draw more often from a stiff total; strong ones usually reach 17 to 21.
| Dealer up card | Dealer position | What it means for you |
|---|---|---|
| 2 and 3 | Weak, but less so than 4 to 6 | Stand on 13 or more, hit 12 |
| 4, 5 and 6 | Weakest: the dealer busts most often from these cards | Stand on 12 or more; double and split more often |
| 7 and 8 | Strong: the dealer often makes 17 or 18 | Hit stiff hands (12 to 16) |
| 9 and 10 | Very strong | Hit stiff hands; surrender 16 (and 15 against a 10) where allowed |
| Ace | Strongest, and a blackjack threat | Hit stiff hands; decline insurance |
That is why the same hand of 12 is played two ways: stand against a 4 to 6, hit against everything else. The chart is simply this logic worked out precisely for every hand.
How basic strategy changes with the rules
Basic strategy is not one chart. It changes with the number of decks, whether the dealer hits soft 17 and whether you can double after splitting. The chart on our blackjack hub assumes 4 to 8 decks, dealer stands on soft 17, double after split and late surrender. When the dealer hits soft 17 (written “H17” on the table felt or in the rules), Wizard of Odds’ chart for the same decks changes these plays:
- Hard 11 against an ace: double instead of hit.
- Soft 18 (ace-7) against a 2: double instead of stand.
- Soft 19 (ace-8) against a 6: double instead of stand.
- Surrender 15 and 17 against an ace, and a pair of eights against an ace, where late surrender is offered.
The rules also move the house edge itself. Wizard of Odds measures each rule against an 8-deck game where the dealer stands on soft 17. The table shows the effect on the player’s expected return, in percentage points (negative = worse for you):
| Rule | Effect on the player |
|---|---|
| Blackjack pays 6:5 | -1.39 |
| Dealer hits soft 17 | -0.22 |
| Double on 10 and 11 only | -0.18 |
| No double after split | -0.14 |
| No hole card | -0.11 |
| Late surrender | +0.07 |
| Single deck | +0.48 |
One rule dwarfs the rest. A 6:5 payout costs more than all the other unfavourable rules on the list combined.
Side bets: what they are and what they cost
Most online tables offer optional side bets next to the main box. They are settled on the first cards and have nothing to do with how you play the hand.
- Perfect Pairs: wins if your first two cards are a pair, with higher payouts for a coloured or perfect (same suit) pair.
- 21+3: your two cards plus the dealer’s up card form a three-card poker hand; flushes, straights, three of a kind and straight flushes pay.
- Hot 3, Bust It and Lucky Ladies: pay on a total of 19 to 21 with three cards, on the dealer busting with a given number of cards, or on a two-card 20.
Side bets pay big multiples, which is the attraction, but their house edges are typically several times higher than the main game played with basic strategy. Each studio and table sets its own pay table, so the same side bet can cost different amounts at different casinos. If you enjoy them, keep the side stake small relative to the main bet and check the table’s paytable in the info panel first.
Card counting explained
Card counting tracks whether the cards left in the shoe favour the player. High cards (tens and aces) help the player: more blackjacks, which pay 3:2, and more dealer busts. Low cards help the dealer.
The best-known method is the Hi-Lo count. Each 2 to 6 counts +1, each 7 to 9 counts 0, and each ten-value card and ace counts -1. The running count is divided by the number of decks left to give the true count. Roughly speaking, each +1 of true count moves the edge about half a percentage point towards the player, so a counter raises bets when the true count is high and bets the minimum otherwise.
Counting is legal, but it has limits. Online RNG blackjack reshuffles before every hand, so the count is always zero. Live dealer shoes are usually cut around halfway, so high counts are rare, and casinos can limit stakes or close accounts they suspect of counting. Continuous shuffling machines at some land tables have the same effect as RNG. For most players the realistic goal is perfect basic strategy, not an edge.
RNG or live blackjack?
| RNG blackjack | Live dealer blackjack | |
|---|---|---|
| Shuffle | Usually before every hand | Shoe dealt to a cut card, often around halfway |
| Free demo | Usually available | Rare |
| Hands per hour | As many as you click, often 200 or more | Far fewer; seven-seat tables are slowest |
| Minimum stakes | Often from EUR 0.50 or EUR 1 | Usually higher; large-format tables are cheapest |
| Rules | Shown in the game’s help screen | Shown in the table’s info panel; check soft 17 and payout |
| Best for | Practice and low stakes | Atmosphere and real cards |
The edge per hand is set by the rules, not the format. A live table with poor rules costs more per hand than a good RNG table, and a fast RNG session can cost more per hour than a slow live one.
Planning a session: a worked example
Say your session budget is EUR 200. A flat stake of EUR 2 to EUR 4 (1% to 2% of the budget) gives room for the normal swings of the game, which are larger than many players expect: the standard deviation of one blackjack hand is a little more than one bet, because doubles and splits put extra money on the table. Over 100 hands at EUR 4, results commonly land EUR 45 or so either side of the average.
The average itself is small. At a 0.5% house edge, 100 hands at EUR 4 means EUR 400 staked and an expected cost of about EUR 2. The danger is not the edge but the swings combined with raising stakes after losses. Decide your stop-loss (for example half the budget) and your stopping time before you start, and keep them.
Blackjack terms you will see online
- Hard and soft hands: a soft hand contains an ace counted as 11; a hard hand does not, or counts the ace as 1.
- S17 and H17: dealer stands on, or hits, soft 17.
- DAS: doubling after splitting allowed.
- Late surrender: giving up half your bet after the dealer checks for blackjack.
- Hole card and peek: the dealer’s face-down card, and the check for blackjack when the up card is an ace or ten. Without a peek (European style), doubles and splits lose to a dealer blackjack.
- Bet behind: betting on another player’s hand at a full live table; you follow their decisions.
- Penetration: how much of the shoe is dealt before the reshuffle. It matters only for card counters.
- Stiff hand: a hard 12 to 16, which can bust with one more card.
Ten useful tips on choosing a table and playing online
- Check the licence first. Look the casino up on its regulator’s register before depositing, and see our checklist of what to look for in an online casino.
- Read the table rules before you sit. The info panel lists decks, the soft 17 rule, doubling and splitting rules and the blackjack payout.
- Insist on 3:2. Leave any table that pays 6:5 or even money on blackjack (unless it is a variant that compensates, such as Blackjack Switch, with its own strategy).
- Prefer “dealer stands on soft 17”. It is worth about 0.2 percentage points.
- Practise in demo mode. Free RNG blackjack lets you drill basic strategy until it is automatic, at no cost.
- Keep a strategy card open. Online it is allowed and expected. Use the chart for the exact rules of your table.
- Skip insurance and even money. Insurance pays 2:1 when the dealer has a ten underneath, but that happens only about 4 times in 13.
- Treat side bets as entertainment. Perfect Pairs, 21+3 and similar bets have house edges far above the main game.
- Do not count on bonuses. Blackjack usually contributes 0% to 10% to wagering, and many casinos exclude it.
- Watch your pace. RNG tables can deal 200 or more hands an hour, live tables far fewer. At the same stake, more hands cost more per hour.
The best hints on selecting a strategy
Separate strategy (how you play each hand) from betting systems (how you size bets). Basic strategy is the only playing strategy that matters for most players. Betting systems such as Martingale or Paroli do not change the house edge; they change the pattern of wins and losses, and progressive systems run into table limits and budgets during losing streaks.
A sensible approach looks like this. Pick a stake at about 1% to 2% of your session budget. Play flat bets. Follow the chart for your table’s rules without exceptions. Stop at a planned time or loss limit. If you want to go further, learn the H17 and single-deck adjustments, then the handful of count-based deviations used by professionals, mostly for interest, since online conditions rarely reward them.
Common myths
- “The dealer is due to bust.” Previous hands do not change the next one, and RNG games reshuffle every hand.
- “Bad players at the table ruin your odds.” Other players’ decisions change which cards you see, but not your long-run expectation.
- “Always assume the dealer has ten.” A rough rule that basic strategy refines: it is right against 7 to ace and wrong against 4 to 6.
- “Never hit 12.” Basic strategy hits 12 against a 2 or 3 and against 7 to ace.
Play responsibly
Blackjack is for adults only: 18+ (higher in some countries). Even with perfect strategy the house keeps an edge, so treat the game as paid entertainment. Use deposit limits and time-outs, and stop if you notice yourself chasing losses. Free help is available from the National Gambling Helpline (GamCare) on 0808 8020 133 in England and Scotland or 0808 2819 265 in Wales, or Gambling Therapy internationally. See our responsible gambling page for more tools, and our casino tips for how blackjack compares with other games.
Frequently asked questions
Where did blackjack originate?
Its direct ancestor is the French game vingt-et-un, played in the 18th century, and Miguel de Cervantes described a similar Spanish game, veintiuna, in a story published in 1613. The modern rules and the name took shape in American gambling halls.
Who invented blackjack basic strategy?
Roger Baldwin, Wilbert Cantey, Herbert Maisel and James McDermott published the first basic strategy in 1956, worked out with desk calculators. Edward Thorp refined it by computer and added card counting in Beat the Dealer (1962).
Does card counting work online?
Not at RNG blackjack, which shuffles before every hand. At live dealer tables the shoe is usually cut around halfway, which limits the advantage, and the casino can restrict your account. Counting is legal, but casinos are not obliged to let you play.
What is the most important blackjack tip?
Play perfect basic strategy at a table that pays 3:2 on blackjack. Those two choices decide most of the house edge; everything else is detail.
Is it better to play blackjack online or in a casino?
The maths is the same for the same rules. Online, you can practise for free, check rules before sitting down and play lower stakes. RNG games are faster, so the hourly cost is higher unless you slow down or lower your stake.
Should you ever take even money in blackjack?
Even money, offered when you hold blackjack against a dealer ace, is the same bet as insurance. Without card counting, decline it: on average you win more by keeping the 3:2 payout.