As in all casino games, the house generally has a clear statistical advantage over the player in the long run.

Under the most favorable conditions (single deck, downtown Las Vegas rules), the house advantage in BlackJack over a basic strategy player can be as low as 0.16%.

Indeed, casinos offering special rules like surrender and double-after-split may actually be offering a positive expectation to skilled players; they are counting on players making mistakes to make money.

Typical conditions are usually 0.5% house edge over a player sticking to the blackjack strategy.

The house edge is a statistically determined value that only begins to apply practically over a very large number of Blackjack hands.
Taking any single hand individually, a player typically has less than 42% chance of winning money.

The house advantage is greatly affected by the rules on offer by the different casinos.

The following rules favour the player:

• Double down on any two-card hand except a blackjack. This allows the player to choose to double when he is most likely to win more.
• Doubles are permitted after splitting. This allows a player to potentially get many bets out in the most favourable circumstances.
• Early surrender; the ability to forfeit half your wager against a face or ace before the dealer checks for blackjack. This is beneficial because some hands a player has are so unlikely to win that its better to just surrender and lose half the bet.
• Normal (aka “late”) surrender.
• Resplitting Aces. This avoids a player getting a miserable total of 12.
• Drawing more than one card against a split Ace. This allows a player to draw a weak soft total if the dealers is showing a high card.
• Five or more cards with the total still no more than 21 as an automatic win (a “Charlie”). This, unfortuneatly, is not a commonly seen rule.

The following rules are detrimental to the player and a game/casino that uses these rules should be avoided:

• Less than 3:2 payout on blackjacks (6:5 and even 1:1 payouts have become common, especially in single-deck games, in Las Vegas). This is the worst rule for the player, the house edge is increased over eightfold.
• Player losing ties. Since a tie will occur almost 8% of the time, a player will lose money up to and over twenty times faster at this type of game. Even in cases where the casino shows both dealer cards face up, allowing the players to see the dealer’s full hand (called Double Exposure), the rule is still more detrimental to the player.

The following rules increase the house edge, but only slightly:

• Dealer hits on soft seventeen (ace, six). This makes the house more likely to land a higher total.
• Splitting a maximum of once (to two hands). This reduces the effect of splitting, since a player may end up with the original hand again.
• Double down restricted to certain totals, such as 9-11 or 10,11. The player cannot hit on soft totals that he may have an advantage at.
• No-Peek (European) blackjack. The player loses splits and doubles to a dealer blackjack, as opposed to only losing original bets.