Blackjack Odds and House Edge

Each row changes one rule of the six-deck reference game and keeps the rest, with basic strategy for the changed game. Costs are given in points, each worth one percentage point of the initial bet, and any rule shown as a link is explained in depth on its own page. A table without a hole card that takes only the original bet when the dealer turns up blackjack costs nothing extra: its edge stays at 0.41%.

Generous rules are rarer than costly ones. Late surrender, given only after the dealer has checked for blackjack, pays off for a player who uses it on the right few hands; early surrender, offered before that check, is worth enough on its own to put the player in front, and almost no table offers it.

Every other rule is the reference game's. Fewer decks favor the player because each card dealt shifts the odds of the next more sharply, which makes blackjacks and good doubles a little more likely. That advantage is why tables with one or two decks so often cut the blackjack payout, a trade the single-deck blackjack page works through.

The payout on a natural is the largest single lever, because every blackjack the player is dealt is paid at the table's rate, and no other line in the rules moves the edge as far as a natural paid at 6:5 or 1:1 in place of 3:2. What that cut takes in money, deck count by deck count, is worked out on the blackjack payouts page.

A dealer who hits soft 17 draws again where another would stop, and the soft 17 rule page follows what that does to the dealer's finishes. Limits on doubling and splitting cost the player in a different way, by removing the moments when more money goes out with the odds in favor; the doubling guide and the pair splitting guide price each of those moments. A dealer who takes no hole card and collects doubles and splits on a later blackjack adds risk to exactly those moments.

The rule: Costs add up close to linearly, so a six-deck table that hits soft 17 and pays 6:5 sits near the sum of both rows above the reference edge, not near either one alone.

Three tables are built around a particular rule from the lists above: American classic around the hole card and the peek, Atlantic City around eight decks with late surrender, and the European game around play without a hole card.

Six decks, with every hand the dealer could hold under that upcard counted, including a blackjack behind a 10 or an ace. Averaged over all upcards, the dealer busts on 28.19% of hands when standing on soft 17 and 28.58% when hitting it. A 6 is the dealer's weakest card and a 7 marks a sharp drop: from 7 to 10, the most likely finish is ten more than the upcard.

Once a dealer who peeks has found no blackjack, the hands still in play are the ones that must be drawn to, so the bust chance rises. Under an ace the two bust columns of the previous table differ the most, a shift the soft 17 page follows. The same ace showing is what brings the insurance offer, a side wager that the blackjack insurance page prices by deck count, along with even money.

The chance of the next card from a full six-deck shoe, before the cards on the table are taken out. An ace counts as one here, so it never busts a hard hand. A high bust chance is not by itself a reason to stand: the right move depends on the dealer's card as well, which the strategy guide works through.

The reference game with basic strategy. Doubles and splits are what put more than the initial bet on the line, in both directions.

Counted by rounds, the player wins 43.35% of them, pushes 8.78% and loses 47.87%. Losing more rounds than winning sounds worse than the house edge suggests, and the gap is closed by money rather than frequency: naturals pay 3:2, and doubles put twice the stake out in exactly the spots where the player is favored.

The standard deviation of a single round, the usual measure of its swing, is 1.15 initial bets, while the house edge takes 0.41% of one. The expected loss grows in step with the number of rounds played, but the typical swing grows more slowly, so it takes a long run before the edge shows through as the steady price of the game.

In short: Over a short session the swing, not the edge, decides whether a player finishes ahead or behind. Play only with money you can afford to lose.