The house edge in blackjack

At our table — six decks, the dealer stands on soft 17, blackjack pays 3 to 2, double after split, no surrender — the house edge with perfect basic strategy is 0.40% of the initial bet. In plain terms, for every 10,000 debens you bet you lose about 40 on average. A 50-million-round simulation of our real shoe gives 0.43% ± 0.03%.

There are two ways to find a house edge, and we used both.

The exact way. A program took every possible start of a round — your two cards and the dealer’s up card from a six-deck shoe — and followed every card that could come next, for every move. Weighted by how often each start occurs, with the dealer’s blackjack, the peek and the 3 to 2 payout included, a round played by our chart averages −0.405% of the bet. If the first decision is allowed to depend on your exact two cards rather than their total, the best possible result is −0.402%. The chart gives away three thousandths of a percent.

The experimental way. A simulator played 50 million rounds with the chart, dealing from a shuffled 312-card shoe and reshuffling when fewer than 78 cards remain, as our dealer does. Result: −0.43% ± 0.03%. With a fresh shoe for every round it gave −0.41% ± 0.03%, right on the exact figure. The difference between the two simulations is within their margin of error.

The edge is an average over many hands, not a fee taken from each one. A single round swings by more than a whole bet: counting doubles and splits, its standard deviation is 1.15 bets. Over 1,000 hands at 100 debens, the expected loss is about 430 debens, but the typical spread around that is ±3,650. A great evening and a terrible one are both ordinary results of the same 0.4%.

Only over tens of thousands of hands does the average start to show through the noise. That is why the edge tells you how to play, not whether you will win tonight.

The dealer has no skill and follows a fixed rule, yet still wins. The reason is one asymmetry: you act first. If you bust, you lose on the spot, even if the dealer would have busted too. A player who simply copies the dealer — hit to 16, stand on 17 — busts in 27% of rounds, and in 8% of rounds both would have busted. That 8% goes to the house.

Some of it comes back. Blackjack pays 3 to 2 and arrives in 4.75% of rounds, which is worth about 2.4% of the bet. That still leaves the copycat 5.7% behind. Basic strategy closes almost all the rest: standing on stiff totals against weak dealer cards, and doubling and splitting, which the dealer is never allowed to do.

We ran the same exact calculation again with one rule changed at a time. A plus means worse for the player:

The blackjack payout dwarfs everything else. A 6 to 5 table takes more than four times as much as ours, and no amount of perfect play wins that back. Anywhere you play, look for “Blackjack pays 3 to 2” on the cloth first; it is the top line on ours.

“Never bust” means standing on any hard 12 or more and hitting soft hands up to 17. It feels safe, and once you also skip doubles and splits it is the costliest habit on the list: you give up every stiff hand against a dealer’s 7 or higher. “Mimic the dealer” plays the dealer’s own game and loses 5.7% because of the bust asymmetry above.

Not in the long run, if all you use is the cards in front of you. Basic strategy is the best possible play without knowing which cards have already left the shoe, and it still loses 0.40%. Betting systems — doubling after a loss, raising after a win — change how your results are spread out, not their average, because every single bet faces the same edge.

The one known way to get ahead is card counting: tracking how many tens and aces are left, betting more when the rest of the shoe favours the player and changing a few decisions, insurance first among them. Real casinos watch for it and show counters the door. In Anubis City there is simply nothing to win: debens are free and can’t be cashed out.

So treat the 0.40% as what it is: the price of the fairest game you can play against the house. Learn the chart, skip insurance and play for the game itself. If it stops being fun, our page on responsible gaming has practical advice.