Should You Split 9s in Blackjack?

Which dealer cards to split against, which to stand on, and why.

Basic strategy says

Split 9s against 2 to 6, 8 and 9. Stand against 7, 10 and ace

A pair of 9s makes 18. That is a good hand, but not a safe one. Splitting is right whenever the dealer is weak or when 18 is not enough to win.

The numbers

These are the average results per £1 of your original bet for a pair of 9s against each dealer card, splitting against standing. They assume an infinite deck, a dealer who stands on soft 17 and checks for blackjack, double after split allowed, and they are calculated exactly, not simulated.

Dealer card	Split	Stand	Best play
2	('+£0.196',)	+£0.122	Split
3	('+£0.259',)	+£0.148	Split
4	('+£0.324',)	+£0.176	Split
5	('+£0.393',)	+£0.200	Split
6	('+£0.472',)	+£0.283	Split
7	+£0.370	('+£0.400',)	Stand
8	('+£0.235',)	+£0.106	Split
9	('−£0.077',)	−£0.183	Split
10	−£0.351	('−£0.242',)	Stand
A	−£0.399	('−£0.377',)	Stand

Against a dealer 7, standing wins about 40.0 pence per £1 on average and splitting about 37.0 pence, because the dealer's most likely total is 17 and your 18 beats it. Against a 10 or an ace, 18 is likely to lose, but splitting is worse, losing about 35.1 and 39.9 pence against 24.2 and 37.7 pence for standing.

Why split 9s against a 9?

Against a dealer 9, standing on 18 loses on average, because the dealer's most common finishing total is 19. Splitting gives you two chances to draw a good hand on top of a 9, and it loses less than standing. It is one of the few cases where you split a hand that is losing either way.

How to play 9s against every dealer card

Here is the pair of 9s row from the basic strategy chart (dealer stands on soft 17, double after split allowed).

	2	3	4	5	6	7	8	9	10	A
9,9	P	P	P	P	P	S	P	P	S	S

H HitS StandD Double (else hit) · Ds Double (else stand)P SplitR Surrender (else hit; 17 v A else stand; 8,8 v A else split)

P means split. S means stand. If the dealer hits soft 17, or you cannot double after a split, the row stays the same.

Other things to know

Always split aces and 8s. Never split 10s or 5s. See when to split pairs for every pair.
Splitting costs a second bet. That is why it only makes sense when each hand has a better average result than one hand would.
Rules matter at the edges. Change the rules in the blackjack calculator to see the advice for your game.

More blackjack strategy guides

Blackjack basic strategy chartA printable chart for hard totals, soft totals and pairs that changes with your table rules.16 against a dealer 10Hit, stand or surrender? The numbers behind blackjack's most famous decision.Soft hands strategyHow to play soft 13 to soft 20, such as ace and 7 or ace and 6.Soft 18 (ace-7)Stand, hit or double? The hand that is most often played wrong.When to double downWhich hands to double on 9, 10 and 11, and the close calls.When to split pairsWhich pairs to split against each dealer card, and which never to split.When to surrenderThe few hands where giving up half your bet is the best move.Dealer hits or stands on soft 17What the rule changes and which plays are different.Blackjack insuranceWhy the side bet loses money, and what even money means.Blackjack house edgeHow much the casino wins, and how much each rule changes it.

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Frequently asked questions

Should I split 9s in blackjack?

Split 9s against a dealer 2 to 6, 8 and 9. Stand against a 7, 10 and ace.

Why not split 9s against a 7?

Because 18 already beats the dealer's most likely total of 17. Standing wins about 40.0 pence per £1 on average, against about 37.0 pence for splitting.

Why split 9s against a 9 if 18 is a good hand?

Because against a dealer 9, standing on 18 still loses on average, and splitting loses less. The dealer's most common total is 19.

Is splitting 9s against a 10 or ace ever right?

No. Standing loses less on average. Splitting puts a second bet at risk against a strong dealer card.