Should You Split 4s in Blackjack? The 4-4 Strategy

Quick answer: In common 4–8 deck blackjack, split a pair of 4s only against a dealer 5 or 6 when double after split (DAS) is allowed. Otherwise, play 4-4 as a hard 8 and hit. This is one of the easiest pair rules to get wrong because “never split 4s” is a useful shortcut—but it is not completely accurate.

The important question is not simply whether you have two 4s. It is whether the table lets you double after splitting. That rule turns 4-4 against 5 or 6 from an ordinary hit into a profitable splitting opportunity relative to the alternatives.

Blackjack 4-4 strategy at a glance

This table describes the standard total-dependent strategy for common multi-deck games. Blackjack strategy is rule-dependent, so use the chart for the rules you actually play. TwentyOne’s interactive blackjack strategy chart is designed for exactly that.

Why splitting 4s feels wrong

A pair of 4s totals only 8. If you do not split, hard 8 is an easy hand: you hit against every dealer upcard. You cannot bust with one additional card, and many draws improve the hand substantially.

Splitting changes that. You put out a second wager and turn one hard 8 into two hands that each begin with a 4. At first glance, that sounds worse. A starting 4 is weak, so why pay to create two of them?

The answer is that against dealer 5 or 6, the combination of a vulnerable dealer upcard and DAS gives each split 4 a chance to become an excellent doubling hand. Draw a 5, 6, or 7 to a split 4 and you may arrive at 9, 10, or 11—exactly the kind of totals that can benefit from putting more money out against a weak dealer card.

That follow-up option is the reason the rule changes. Without DAS, much of the value of splitting disappears.

When should you split 4s?

For a typical 4–8 deck game:

• 4-4 vs 5 with DAS: split.
• 4-4 vs 6 with DAS: split.
• Every other dealer upcard: hit.
• If DAS is not allowed: hit 4-4 against everything.

This is a narrow splitting range, which makes it easy to memorize: 4s split only into 5 or 6, and only with DAS.

That is also why you should check the table rules before playing. Our guide to DAS vs. NDAS explains how the same rule changes several other pair decisions.

Why dealer 5 and 6 are special

Dealer 5 and 6 are among the weakest upcards because the dealer must continue drawing according to fixed rules and frequently has to build a hand from an awkward starting total. But “the dealer might bust” is not enough by itself to justify a split.

Basic strategy compares the expected value of all legal actions. With 4-4, hitting keeps a perfectly playable hard 8 intact. Splitting becomes better only in the narrow situations where the value of creating two hands—and potentially doubling them after the split—outweighs the value of simply hitting the 8.

This is an important general lesson: dealer weakness does not mean you should automatically stand or split. The correct play depends on the value of your available actions. You can see the dealer’s relative vulnerability in our dealer bust odds by upcard guide.

How much does the 4-4 mistake matter?

The 4-4 split is a good example of a decision that is mathematically real but relatively rare. Wizard of Odds has analyzed the common mistake of hitting 4-4 against 5 or 6 when DAS is available. In its six-deck analysis, hitting instead of splitting costs about 2.83% of the initial wager against a 5 and 4.38% against a 6 when that situation occurs.

Those percentages do not mean your overall house edge rises by several percentage points. The hand occurs infrequently. The same analysis estimates that always making this mistake increases the overall house edge by only about 0.0032 percentage points.

So 4-4 is worth learning, but it also illustrates a useful training priority: frequent errors such as missed doubles can matter more to your long-run results than an obscure pair decision you see rarely.

What happens after you split 4s?

Once you split, stop thinking of the cards as a pair. You now have two separate hands, each beginning with a 4, and you play the new total according to basic strategy.

Suppose you split 4-4 against a dealer 6 in a DAS game:

• If the first 4 receives a 6, you have hard 10 and can double under normal DAS rules.
• If it receives a 7, you have hard 11, another powerful doubling total.
• If it receives a 10-value card, you have hard 14 and play that hand as hard 14.
• If it receives another 4 and resplitting is allowed, consult the appropriate pair strategy again.

The ability to double those favorable post-split totals is exactly what makes the original split worthwhile.

What if double after split is not allowed?

If the table is NDAS—no double after split—the standard multi-deck answer becomes very simple: do not split the 4s; hit the hard 8 instead.

Imagine splitting against a 6 and then drawing a 6 to one of your 4s. You now have a 10 against a weak dealer card, but NDAS prevents you from doubling. You have given up one of the main advantages that justified creating the extra hand.

This is why memorizing pair strategy without learning the table rules can produce errors. DAS is not merely a procedural detail. It changes the optimal decision itself.

Is 4-4 the same as hard 8?

Only when splitting is not the best option. A pair is special because splitting gives you an additional legal action. If basic strategy says not to split, you fall back to the underlying total—in this case, hard 8.

Hard 8 is hit against every dealer upcard in conventional multi-deck basic strategy. So against dealer 2–4 or 7–Ace, your pair of 4s behaves exactly like any other hard 8. It also behaves like hard 8 against 5 or 6 when DAS is unavailable.

This “pair first, total second” workflow is useful when reading a blackjack strategy chart: check whether the hand qualifies for a split; if it does not, play the underlying hard total.

Does H17 vs. S17 change the 4-4 rule?

For the standard multi-deck 4-4 decision described here, the key switch is DAS rather than whether the dealer hits soft 17. The familiar rule remains: split against 5 and 6 with DAS; otherwise hit.

H17 and S17 absolutely matter elsewhere on the chart, including some doubles and surrender decisions. If you are learning a specific casino game, read the felt or table placard and use the matching strategy. Our H17 vs. S17 guide covers the differences.

Does deck count change pair-of-4s strategy?

Deck count can change blackjack strategy at the margins, especially in single- and double-deck games. That is why a strategy chart should always match the rules being played rather than pretending one chart is universal.

For the common 4–8 deck game this article targets, the DAS-dependent 5-or-6 rule is the standard baseline. If you play single deck or double deck, use a chart built specifically for that deck count. Our guide to how deck count affects blackjack explains why seemingly small rule differences matter.

Why “never split anything that starts with F” is wrong

You may hear a casino shortcut along the lines of “never split 4s, 5s, or face cards.” It is memorable, but it mixes a good rule with an important exception.

5s should not be split in standard basic strategy because 5-5 is a strong hard 10. Our pair of 5s strategy guide explains why keeping the 10 together is so valuable.

4s are different. They usually should not be split, but DAS creates the 5-and-6 exception. That is why rule-aware strategy beats slogans.

A simple way to memorize 4-4

Use this sentence:

“Four-four: five or six, but DAS is the trick.”

If DAS is available, split against 5 or 6. If it is not, hit. Against every other upcard, hit.

Then connect it to the surrounding pair rules. 5-5 is never split in ordinary basic strategy, while 6-6 has a wider splitting range. Learning neighboring pairs as contrasts is often easier than memorizing isolated chart cells.

Common mistakes with a pair of 4s

Splitting 4s against every weak dealer card

Dealer 2, 3, and 4 are not enough. In the standard multi-deck game, 4-4 splits only against 5 and 6—and only with DAS.

Never splitting 4s

This is the opposite error. The shortcut works most of the time, but misses the DAS exceptions against 5 and 6.

Ignoring DAS

This is the biggest conceptual mistake. The post-split doubling opportunity is a central reason the split becomes worthwhile.

Doubling the original hard 8

Do not confuse the value of doubling after the split with doubling the original 8. The original 4-4 is either split or hit under the common rules discussed here.

FAQ

Should you ever split 4s in blackjack?

Yes. In common 4–8 deck blackjack, split 4-4 against dealer 5 or 6 when double after split is allowed. Otherwise hit.

Should you split 4s against a dealer 6?

Split if DAS is allowed. If the table does not allow doubling after a split, hit the hard 8 instead.

Should you split 4s against a dealer 5?

Yes with DAS in standard multi-deck basic strategy. Without DAS, hit.

Should you split 4s against a dealer 4?

No. Hit. Although dealer 4 is a weak upcard, the expected value does not justify splitting 4-4 in the standard multi-deck game.

Should you split 4s against a 2 or 3?

No. Treat the pair as hard 8 and hit.

Should you split 4s against a 7, 8, 9, 10, or Ace?

No. Hit the hard 8.

Why does DAS change the answer?

Splitting creates two hands starting with 4. Against dealer 5 or 6, some next cards turn those hands into strong doubling totals. DAS lets you capitalize on those favorable draws; NDAS does not.

The bottom line

A pair of 4s is a small but excellent test of whether you are learning real, rule-dependent basic strategy rather than casino folklore.

For common multi-deck blackjack: split 4-4 against 5 or 6 with DAS. Otherwise hit.

Once that rule is automatic, continue through the complete blackjack pair-splitting guide or practice the decisions with the interactive strategy chart.