Blackjack Rules and House Edge: Which Games Are Worth Playing

By CardCount Academy · Reviewed October 5, 2026 · 9 min read

Two blackjack tables can sit side by side, look identical, and differ by a factor of four in how much they cost you to play. The difference is in the rules — and for a card counter, in how deep into the shoe the dealer goes before shuffling. This guide explains what the house edge is, how each rule moves it, and how to judge a game before you put a chip down.

What the house edge is

The house edge is the share of your initial bet that you lose on average, over a very large number of hands, if you play perfect basic strategy. An edge of 0.5% means that for every $100 bet you lose 50 cents on average. It says nothing about any single session: in the short run the swings are many times larger than the edge.

Blackjack's edge comes from one asymmetry: you act first. If you bust, you lose immediately, even when the dealer goes on to bust as well. Everything else in the rules — the 3:2 payout on blackjack, doubling, splitting, the dealer's fixed drawing rules — gives part of that advantage back.

A benchmark game

A common fair game is six decks, dealer stands on soft 17, double on any two cards, double after split, blackjack pays 3:2. With perfect basic strategy the house edge is a little over 0.4%. That is the game our simulator deals, and a useful reference point for everything below.

How each rule moves the edge

The figures below are the changes published by the Wizard of Odds, measured against an eight-deck game. A plus sign is worse for the player.

The effects add up, approximately. Take the benchmark game and switch the dealer to hitting soft 17, and the edge goes from about 0.4% to about 0.6%. Change the payout to 6:5 as well and it is close to 2% — nearly five times the starting figure, and beyond what a realistic count can overcome.

Why 6:5 matters so much

You are dealt a blackjack about once every 21 hands. On a $10 bet, 3:2 pays $15 and 6:5 pays $12. Losing $3 once every 21 hands is 14 cents per hand, or 1.4% of your bet — on top of the edge the game already had. No other common rule comes close, and it is often paired with a sign that makes it sound generous. Read the felt before you sit down.

The number of decks

Fewer decks are better for the player, mostly because blackjacks are slightly more frequent and doubling is slightly more effective when removing a few cards changes the composition more. The steps get smaller as decks are added: going from one deck to two costs far more than going from six to eight.

In practice the number of decks rarely comes alone. Single-deck games today almost always pay 6:5, and double-deck games often restrict doubling or hit soft 17. Compare the complete rule set, not one headline feature.

Penetration: the rule that isn't printed

Penetration is how much of the shoe is dealt before the shuffle. It has no effect at all on a basic strategy player — every round is, on average, the same. For a counter it is as important as all the printed rules together.

The reason is that the true count only reaches high values when few cards are left. If a six-deck shoe is cut with two decks behind the cut card (about 67% penetration), strongly positive counts are rare. With one deck cut off (about 83%), they are several times more frequent. A game with average rules and deep penetration is usually a better counting game than one with excellent rules and a shallow cut.

What a counter looks for

1. 3:2 on blackjack. Non-negotiable.
2. Penetration. In a six-deck game, 75% or more (a deck and a half or less behind the cut card).
3. Hand-shuffled or a batch shuffler. A continuous shuffling machine puts the cards back after every round, which makes counting pointless — see the countermeasures guide.
4. S17, double after split, surrender. Each one helps, in roughly that order.
5. Table conditions. Fewer players means more hands per hour and more of the shoe seen per round; a higher table minimum means larger swings for the same edge.

House edge versus what you actually lose

The edge is measured per hand, but your expected loss depends on how many hands you play. At a full table you might see 60 hands an hour; alone with the dealer, well over 150. At $10 a hand and a 0.5% edge, that is an expected cost of about $3 an hour at the full table and $7.50 heads-up — before the far larger effect of luck.

The same arithmetic is what makes counting slow. A counter's average advantage is typically around 1% of the money wagered, so the expected hourly win is small compared with the swings. The bankroll guide works through the numbers.

Side bets

Perfect pairs, 21+3, "lucky ladies" and similar side bets usually carry a house edge several times higher than the main game. They are a separate wager on a separate, worse game. Basic strategy ignores them, and so does a Hi-Lo count: the main count says little about most side bets.

The short version

Find 3:2, avoid continuous shufflers, prefer S17 and double after split, and — if you count — watch where the cut card goes before anything else. A good game with a mediocre count beats a bad game with a perfect one.

Sources and further reading

• Wizard of Odds — Blackjack Rule Variations
• Wizard of Odds — 4-Deck to 8-Deck Blackjack Strategy
• Peter A. Griffin, The Theory of Blackjack (Huntington Press).
• Don Schlesinger, Blackjack Attack: Playing the Pros' Way (RGE Publishing) — origin of the "Illustrious 18".