When to Split in Blackjack: Every Pair, Every Upcard

The Complete Pair Splitting Chart

Standard rules: 6 decks, dealer stands on soft 17, double after split (DAS) allowed. Cells marked with a dot are splits only with DAS - without it, hit instead.

P = Split · H = Hit · S = Stand · D = Double · • = split only with DAS

The Two Unconditional Splits: Aces and 8s

A,A: a 12 that hits terribly, or two hands that each start with the best card in the deck. Splitting Aces is the most profitable move in blackjack, worth about half a bet in extra expectation against most upcards. Most casinos deal only one card to each split Ace - split them anyway. Even against a 10.

8,8: hard 16 is the worst total in the game; two hands starting from 8 lose less against every single upcard. Against a dealer 10 it feels like throwing good money after bad - the math says split anyway. The one exception worth knowing: against an Ace in H17 games with surrender, surrendering 8,8 edges out the split.

The full story of both hands is in Splitting Aces and 8s.

The Two Never-Splits: 10s and 5s

10,10: you're holding 20. Even against a dealer 6, where splitting is technically profitable, standing is more profitable. Only counters at strongly positive counts split 10s, and doing it at a normal table marks you as either a beginner or a counter - neither is good.

5,5: this is not a pair, it's a 10 - one of the best doubling hands in the game. Double against 2-9, hit against 10 and Ace, and never turn one strong hand into two terrible ones.

The Conditional Splits

9,9 - split against 2-6, 8, and 9; stand against 7, 10, and Ace. The strangest row on the chart: your 18 beats a dealer 17, so you stand against a 7 (dealer's most likely total: 17), but 18 loses to a made 19 or 20, so against an 8 or 9 you split to fight two battles from 9 instead of losing one from 18. The 9,9 vs 7 logic in full.

7,7 - split against 2-7. A 14 is a loser; two 7s against a weak upcard are two chances at 17+ while the dealer breaks. Against 8 or higher, just hit the 14.

6,6 - split against 2-6 (the 2 needs DAS). A 12 is a stiff either way; against bust cards you'd rather have two hands in play while the dealer breaks. Why the 2 is the marginal case.

2,2 and 3,3 - split against 2-7 (the 2 and 3 need DAS). Low pairs make miserable totals (4 and 6 hit into stiffs constantly), so against anything but a strong upcard you break them up. The small-pair logic explained.

4,4 - split only against 5-6, only with DAS. A hard 8 hits fine, so the split needs the dealer's two weakest cards plus the chance to double a caught 5, 6, or 7. The most marginal split on the chart.

Three Table Rules That Matter for Pairs

• DAS (double after split): flips seven marginal cells from hit to split - see the dots on the chart. Always check whether the table allows it.
• Resplitting: most tables let you split up to 3 or 4 hands. If you split 8s and draw another 8, split again - the logic that justified the first split hasn't changed.
• Split Aces get one card: nearly universal. You can't hit or double after splitting Aces, and a 10 on a split Ace is 21, not blackjack. Split them anyway.