How Many Decks, and Does It Matter?

Updated

Six or eight decks is the modern standard, dealt from a shoe. Fewer decks genuinely help you, but far less than most players believe — and that gap is exactly the trap that single-deck 6:5 tables are built on.

The short version
Every figure here is computed with our own solver and checked against an independent reference. The calculator applies the same numbers to your table.

What deck count is worth

Computed for otherwise identical rules: dealer stands on soft 17, double on anything, double after split, no surrender, blackjack pays 3:2.

DecksHouse edgeAgainst six decks
1-0.16%-0.612%
20.22%-0.235%
60.46%
80.48%+0.029%

Fewer decks help for two reasons. You are dealt a blackjack slightly more often, and the cards you hold change the remaining shoe more, which makes doubling and splitting land better.

1 deck -0.16% 2 decks 0.22% 6 decks 0.46% 8 decks 0.48%
The whole range from one deck to eight is smaller than a single bad payout rule.

The single-deck trap

A single-deck game is worth about 0.61% to you against six decks. A 6:5 payout costs 1.36%.

So a single-deck table paying 6:5 is substantially worse than a six-deck table paying 3:2 — and it is advertised as the better game, because “single deck” sounds like an advantage and everyone has heard that fewer decks are good.

If you take one thing from this page: check the payout before you count the decks.

For counters it is a different question

Deck count barely moves a counter’s earn rate. Penetration does, enormously — going from 50% to 75% multiplies the hourly rate by nearly seven, while going from eight decks to one moves the base edge by a fraction of a percent.

Fewer decks do make the true count swing faster, which is useful. But a deeply dealt eight-deck shoe beats a shallow single-deck game every time.

Keep reading

3:2 against 6:5the rule that matters more Penetrationwhat counters should look at Every rule, pricedin context

By Martin Kosek · every number on this site is computed by us, not copied.

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