When to split in blackjack: every pair, explained

How splitting works

When your first two cards have the same value, you can split them. Ten-value cards count as a pair, so king + jack can be split, though it shouldn't be. You put down a second bet equal to the first, and each card becomes the start of its own hand. Each hand then gets a second card and is played separately, one after the other.

If one of those hands is dealt another matching card, you can split again, up to four hands at this table. Split aces are the exception: each ace receives exactly one card and then stops. An ace and a ten after a split counts as 21, not blackjack, and pays even money.

The pair-splitting chart

P means split. Otherwise follow the action shown: H hit, S stand, D double.

Always split aces

Two aces together make soft 12, a feeble total. Split, each ace starts a new hand with the best card in the deck. Nearly a third of the cards are worth ten, so each split ace has a good chance of becoming 21, and most other cards still give you a respectable 17 to 20. Even though each ace gets only one card, splitting is far better than playing soft 12.

Always split eights

Two eights make hard 16, the worst total in blackjack. It's too low to stand on against a strong dealer and very likely to bust if you hit. Splitting replaces one terrible hand with two hands that each start from 8, which can still become 18 with a ten.

Splitting eights against a dealer 10 or ace looks like throwing good money after bad, and in a sense it is. Both options lose money on average. Splitting simply loses less than playing 16. Basic strategy isn't always about winning a hand. Sometimes it's about losing as little as possible.

Never split tens

Twenty is the second-best hand in the game. Against any dealer card it wins far more often than it loses. Splitting it trades a near-certain winner for two hands that each start from 10, and each of those is worse on average than the 20 you gave up. Tens are a stand, every time.

Never split fives

A pair of fives is really a hard 10, one of the best doubling hands you can hold. Split them and you get two hands starting from 5, which is a bad starting card: it easily lands you on 15 or 16. Treat 5,5 as a 10 and double it against 2 through 9, or hit against a 10 or ace.

Nines: split, except against 7, 10 and ace

Eighteen is a decent hand, but against a weak dealer upcard, two hands starting from 9 earn more than one 18. The exceptions:

• Against a 7, stand. The dealer's most likely finishing total with a 7 showing is 17, and your 18 already beats that. There's nothing to gain by splitting.
• Against a 10 or ace, stand. The dealer is strong, and two hands from 9 would mean doubling your money in a bad spot. Standing on 18 loses less.

Splitting nines against an 8 but not a 7 surprises people. Against an 8, the dealer often makes 18, which only ties your 18. Two hands starting from 9 have a better chance of beating it.

Sevens, sixes, threes and twos: split into weakness

These smaller pairs all follow the same rule: split when the dealer is weak, hit when the dealer is strong.

• 7,7 is hard 14. Split against 2 through 7. Against 8 and above, hit.
• 6,6 is hard 12. Split against 2 through 6. Against 7 and above, hit.
• 3,3 and 2,2 split against 2 through 7, and hit against 8 and above.

When the dealer is likely to bust, more hands on the table means more money riding on that bust. When the dealer is likely to make a strong hand, you want as little money out as possible.

Fours: split only against 5 and 6

A pair of fours is hard 8, which you'd normally just hit. It's worth splitting only against a 5 or 6, and only because this table lets you double after splitting. Each 4 that catches a 6 or 7 becomes a 10 or 11 that you can double against a weak dealer. In a game without double-after-split, fours are never split.

How table rules change splitting

Pair decisions are more sensitive to the rules than any other part of the chart. Double after split is the biggest factor. Without it, you split twos, threes and sixes in fewer spots and never split fours. If you play somewhere with different rules, check a chart built for them. This guide only covers the rules used at this table.

Keep learning

Splitting and doubling often happen together. Read when to double down next, or see the whole strategy chart.