Casino games are games of chance with a built-in house edge. No strategy, system or timing changes the odds in the player’s favor over time, and most players lose money over the long run. Nobody should gamble money they cannot afford to lose. Blackjack is often described as a low-edge game, but how low depends on the rules of the particular table.
Same game, different price
Two blackjack tables can look identical and still differ in cost. The difference lies in small rules printed on the felt or posted on the sign: how many decks are used, what a natural pays, what the dealer does on a soft 17, and which doubling, splitting and surrender options exist. Each rule moves the house edge by a small amount, and several together can add up. The numbers below are described only in direction, because exact figures vary by the complete rule set, and quoted values should be checked against a reliable calculation rather than assumed.
Number of decks
Blackjack is played with anywhere from one to eight decks, commonly in a shoe for the larger counts. Generally speaking, more decks give the house a slightly higher edge, other rules equal. The difference between single-deck and eight-deck play is typically a few tenths of a percentage point, not several points.
Why does the deck count matter? One reason is how often a natural occurs. With a single 52-card deck, the probability of being dealt an ace and a ten-value card as your first two cards is 2 × (4/52) × (16/51) = 128/2652, about 4.83 percent. With a very large number of decks it approaches 2 × (1/13) × (4/13) = 8/169, about 4.73 percent. A natural is a premium result, so seeing it a little less often makes the game slightly worse for the player. Some other effects work the same way: with fewer decks, removing cards from the pool changes later probabilities slightly, which helps in a few situations.
Fewer decks also matter for card counting, because information from cards already seen is more useful when fewer cards remain. That is a major reason venues change deck counts and shuffle often, and it is part of the broader pattern of rule changes in casino history. Continuous shuffling machines and shuffle points also change the effective game. The point here is only that the deck count is a rule with a cost attached, not that any deck count offers an advantage.
Payout for a natural
This rule has the largest effect among the common ones. On a bet of 10 units, a natural paying 3 to 2 returns 15 units of profit; paying 6 to 5, it returns 12. The 3 units difference occurs on roughly one hand in twenty, which is enough to raise the house edge by an amount many sources put at well over one percentage point. Reading the table sign for the ratio is one of the quickest checks available. Payout ratios in X to Y notation are explained in a separate article.
Dealer rules on soft 17
A soft 17 is a hand worth 17 that includes an ace counted as 11. At some tables the dealer stands on soft 17; at others the dealer hits it. Hitting gives the dealer a chance to improve the hand, which raises the house edge. The rule is usually printed on the felt. The same idea of soft hands appears in player decisions and is covered elsewhere.
Options for the player
Several rules give the player additional choices, and each such choice, if available, reduces the edge slightly:
- Doubling after a split. Allowing a double down on hands made from a split.
- Doubling restrictions. Some tables limit doubling to certain totals, such as 9 to 11; fewer restrictions favor the player.
- Re-splitting pairs. Being allowed to split again after a split.
- Late surrender. Giving up a hand for half the stake after the dealer checks for a natural.
- Number of cards. Some rule sets pay on special hands such as a multi-card total without busting; these are not universal, and are best read from the table.
Rules in the opposite direction include dealer hitting soft 17, no doubling after split, and fewer splitting options.
Ties and dealer variations
Ordinarily a tied hand is a push and the stake is returned. A few variations treat particular ties, such as a dealer total of 22, as a push instead of a player win, which increases the edge. The effect of tie handling is explored in the article on push rules.
Using the rules to compare tables
Because several rules interact, no single rule decides the cost. Some players and writers use published calculators or tables that combine the full rule set into one edge figure, and this is a better approach than guessing from one rule. Basic strategy is the set of decisions that minimizes the edge for a given rule set, and it changes slightly when the rules change. Even then, it reduces the cost; it does not remove it.
Once you have an edge for a table, the cost per hour follows from the speed of play and the average bet. A lower edge combined with a faster dealing speed can still mean a higher hourly cost than a slower table with a somewhat higher edge.
What to keep in mind
A favorable rule set shrinks the house edge but does not reverse it in ordinary play, and results over a session vary widely around the average. Decide in advance how much you can afford to spend, and stop when you reach it. If gambling is causing difficulty, a local support service can help.