Blackjack variants: get the best house edge

There are a few different versions of blackjack, with distinct rules and odds.

As a centuries-old casino classic, blackjack has diversified into a variety of different games. Many players enjoy mixing up their play by trying their hands at alternatives to standard blackjack rules. Be warned, the information in our blackjack strategy guide will not apply to these variants.

Blackjack variations

Below are the most popular blackjack variants hosted by online casinos, organised from lowest to highest house advantage. All assume players bettors use basic strategy.

Caribbean 21

This game made the news in 2003 when a player won $1.3 million playing Caribbean 21 at Hampton Casino. The RTG-run casino however refused to pay, claiming the player had used a software bot to hack a flaw in the Caribbean 21 software. The player and the casino eventually came to an undisclosed settlement.

Caribbean 21 has the largest number of preferable rule changes that, by playing perfect strategy, can reduce the house edge to a measly 0.19 percent. Aces are always low, and players can hit, stand, double down, split (when applicable) or surrender whenever they wish. The dealer wins all ties, and the only hand that pays more then evens is 'Caribbean 21' which is two tens or court cards and an ace, which pays 3/2.

House edge: 0.19%

Spanish 21

Spanish 21 helps to swing the odds in favour of the player, although the house still retains an edge, of course. The deck used has only 48 cards – a "Spanish" deck in which all four tens are removed. There are many additional rules that make this a very interesting blackjack variant:

  • Late surrender, doubling after a split and re-splitting aces are all allowed
  • A player scoring 21 always wins, including blackjack
  • Players can double down on any number of cards
  • Players can hit and double down after splitting aces
  • Players can surrender after doubling down
  • A five-card 21 pays 3/2, a six-card 21 2/1 and a seven card 21 3/1, unless the player has double downed or split
  • 678 or 777 of mixed suits pays 3/2, and of the same suit 2/1, and of spades 3/1
  • Suited 777 when the dealer has a seven as an up card pays a tasty bonus

Note – not all versions of Spanish 21 will honour all rules, so check with your chosen casino before playing.

House edge: 0.40%

21st Century Blackjack

AKA ‘Vegas Style’ blackjack. This variant is played in California card rooms. Player busts are not always considered automatic losses. Players can sometimes collect if the dealer also busts, although the dealer must bust with a higher total.

House edge: 0.44%

Blackjack Switch

A version in which a player plays two hands at once. Once the player's two hands have been dealt, the player has the option to switch cards to make better hands. For example, if a player is dealt 6J and Q5, they can switch to make better hands, in this case 65 and JQ.

The trade-off with this game is that a dealer scoring 22 results in a push, and blackjacks only pay even money.

House edge: 0.58%

Double Attack Blackjack

A popular game in Atlantic City, in Double Attack Blackjack (played with a Spanish deck) the player has the option of doubling his bet when the dealer's up card has been dealt. There are multiple variations associated with this version – such as dealers standing on soft 17, doubling after a split allowed, aces may not be re-split and so on. If you play Double Attack Blackjack it's best to check all the rules that are in play.

House edge: 0.62%


This is the version of the game that most players in the UK will have grown up with. There are again many possible different rules, so its best to check with the casino before you start playing. The main rule differences are that the dealer hits soft 17, doubling after a split is allowed, players may double down on 9 and 11 only, and a player 21 or blackjack is an instant winner.

House edge: 0.64%

Double Exposure Blackjack

Identical to standard blackjack, except that the dealer’s first two cards are both played face up. The trade off to this added feature is that the dealer wins if there would otherwise be a push (except on a natural blackjack), a player blackjack only pays 2/1, and re-splitting is not allowed. There are other slight variations as well.

House edge: 0.66%

Super Fun 21

This is an online version of a game that is popular in Vegas casinos that has been adapted for online play. There are lots of extra possible rules, such as re-splitting being allowed up to a maximum of four hands, doubling is available on any number of cards, and a non-doubled, non-busted hand of six cards or more automatically wins. The trade-off on this occassion is that blackjacks (except a blackjack in which both cards are diamonds, which pays 2/1), pay evens.

House edge: 1.16

The right casinos to play blackjack

Try out these blackjack variants at the best online casinos for blackjack fans.

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