When to split in blackjack depends on the pair and the dealer's card: always split aces and 8s, never split 5s or 10s, and split 2s, 3s, 6s, 7s and 9s against weaker dealer cards. Splitting turns one pair into two hands with a second equal stake, so each split doubles the money at risk.
2s, 3s, 6s, 7s and 9s are split against weaker dealer cards; 4s only against a 5 or 6.
The 2s, 3s, 4s and 6s plays depend on whether you can double after splitting.
Any splittable pair turns up on about 14.6% of eight-deck starting hands.
No re-splitting costs the player 0.10%; no splitting at all costs 0.57%.
Always split
Aces and 8s
Never split
5s and 10s
Stake needed
A second bet equal to the first
Split aces
One card each at most tables
No splitting allowed
Costs the player 0.57%
How splitting works in blackjack
When your first two cards are a pair, you may split them into two separate hands. You place a second stake equal to the first, the dealer moves one card across, and each card receives a new second card. You then play each hand on its own. According to the Wizard of Odds blackjack basics (opens in a new tab), any two ten-point cards also count as a pair, split aces receive only one card each, and re-splitting is usually allowed up to four hands, though some casinos restrict it.
Splitting is one of the four main choices covered in our blackjack guide, alongside hitting, standing and doubling. The split glossary entry gives the short definition, and re-split covers what happens when a split hand pairs again.
Pairs, 4–8 decks, dealer stands on soft 17, double after split allowed
Pair
2
3
4
5
6
7
8
9
10
A
A,A
P
P
P
P
P
P
P
P
P
P
10,10
S
S
S
S
S
S
S
S
S
S
9,9
P
P
P
P
P
S
P
P
S
S
8,8
P
P
P
P
P
P
P
P
P
P
7,7
P
P
P
P
P
P
H
H
H
H
6,6
P
P
P
P
P
H
H
H
H
H
5,5
D
D
D
D
D
D
D
D
H
H
4,4
H
H
H
P
P
H
H
H
H
H
3,3
P
P
P
P
P
P
H
H
H
H
2,2
P
P
P
P
P
P
H
H
H
H
Key: P = split, S = stand, H = hit, D = double (hit if not allowed). Where a pair is not split, play it as the hard total it makes: 5,5 is a hard 10 and 10,10 is a hard 20. Where surrender is offered, the chart never surrenders 8,8; it splits. Our interactive strategy chart shows the same plays.
Pair by pair: the reasoning
Aces and 8s: always
Two aces make a clumsy soft 12; split, each ace becomes the start of a hand that makes 21 with any ten-value card. Two 8s make 16, the worst total in the game. Split, each 8 starts a hand that can be built into something better. Both cases have a page of their own: splitting aces and eights.
5s and 10s: never
A pair of 5s is a hard 10, one of the best doubling hands, while a single 5 is a poor start. A pair of 10s is 20, which wins most hands; breaking it up swaps a strong made hand for two weaker starts.
9s: split, except against 7, 10 and ace
Eighteen is decent but not dominant. Against a 2 to 6 or an 8 or 9, two hands starting with 9 do better than one 18. Against a 7, your 18 already beats the dealer's most likely 17, so you stand. Against a 10 or an ace, splitting puts more money against a strong card, so you stand.
2s, 3s, 6s and 7s: split against weak cards
Together these pairs make weak totals of 4, 6, 12 and 14. Against a dealer 2 to 6 or 7 (2 to 6 for 6s), starting two hands with a small card is better than playing a poor total. Against 8 or higher, splitting would mean two weak hands against a strong card, so you hit.
4s: only against a 5 or 6, with DAS
Eight is a reasonable hitting total. You only split 4s against the dealer's two weakest cards, and only because you can double the hands that follow.
How double-after-split changes the chart
Whether you can double a hand after splitting it changes four rows. When a small pair is split against a weak dealer card, the best result often comes from drawing to 10 or 11 and doubling. Take that option away and some splits stop paying.
Pair plays with and without double after split
Pair
With DAS: split against
Without DAS: split against
2,2
2 to 7
4 to 7
3,3
2 to 7
4 to 7
4,4
5 and 6
Never (hit)
6,6
2 to 6
3 to 6
7,7, 8,8, 9,9, A,A
Unchanged
Unchanged
The Wizard of Odds rule variations (opens in a new tab) table puts the cost of no double after splitting at 0.14% to the player. Lightning Blackjack, according to Wizard of Odds, allows only one split and no double after splitting, so check how a branded game handles both before relying on any chart. Our page on when to double down lists the doubles that follow a split.
How often you are dealt a pair
Counting the cards in an eight-deck shoe shows how often these decisions come up. There are 416 cards, 32 of each rank and 128 ten-value cards in total.
Chance of each pair as your first two cards, eight decks
Starting hand
Working
Chance
About 1 in
One particular pair, e.g. 8,8
32/416 × 31/415
0.57%
174
Any pair of 2s to 9s or aces (9 ranks)
9 × 0.57%
5.17%
19
Any two ten-value cards
128/416 × 127/415
9.42%
11
Any splittable pair
5.17% + 9.42%
14.59%
7
Most splittable pairs are two ten-value cards, which you never split. A specific pair such as aces or 8s turns up only about once in 174 hands, so the pair rows are the least used part of the chart, yet mistakes there cost money each time because the stake usually doubles. For more counting of this kind, see casino probability basics.
What splitting does to your stake: examples
Splitting 7s against a 6. You bet £10 on 7,7. You split, adding £10. Hand one draws a 4 for 11 and you double it, adding another £10. Hand two draws a 10 for 17 and you stand. You now have £30 on the table from a £10 opening bet. If the dealer busts, you collect £30 profit; if the dealer makes 19, you lose £30. That is why splits deserve room in your budget.
Re-splitting 8s. You bet £5 on 8,8 against a 10 and split. The first hand draws another 8; at a table that allows re-splitting, you split again to make three hands and £15 in play. Wizard of Odds measures a no-re-split rule at 0.10% against the player.
The pace of the game. With a European no-peek edge of 0.62% (six decks, as analysed by Wizard of Odds), a £10 player averaging £12 in play per round, after splits and doubles, would expect to lose about 7.4p a round on average. Over an illustrative 70 rounds an hour that is about £5.21. The cost per hour page explains the method.
How to split a pair online
Check the help screen: how many times you can re-split, whether you can re-split aces, and whether doubling after a split is allowed.
When dealt a pair, look up the pair and the dealer's card in the chart.
If the chart says split, press Split. A second stake equal to the first is placed.
Play the first hand to the end using the hard or soft chart, including doubles if allowed.
Move to the second hand and play it the same way.
If a hand pairs again and re-splitting is allowed, check the pair row again before deciding.
Splitting rules and their cost
Rules around splitting vary between games. Against the Wizard of Odds eight-deck, stand-on-soft-17 baseline, these are the measured effects.
Splitting rules and the player
Rule
Effect on the player
No splitting at all
−0.57%
No splitting aces
−0.18%
No re-splitting
−0.10%
No double after split
−0.14%
Re-splitting aces allowed
+0.08%
European no hole card (splitting share)
−0.03%
The last row matters because, in no-hole-card games, a dealer blackjack can take your split stakes as well as the original one under the European no-peek rule as analysed by Wizard of Odds. That makes splitting against a ten or an ace riskier in those games. Our European blackjack page explains, and blackjack house edge shows how the rules combine.
Power Blackjack removes the 9s and 10s and allows doubling, tripling or quadrupling even after a split. See Power Blackjack.
Lightning Blackjack allows one split only, according to Wizard of Odds. See Lightning Blackjack.
Splitting myths and mistakes
Splitting 10s against a weak card. It can look clever against a dealer 6, but 20 is a strong hand. Standing is the play.
Splitting 5s. Play them as a hard 10 and double against 2 to 9.
Refusing to split 8s against a 10 because it 'throws good money after bad'. Sixteen against a 10 is already a losing position; splitting is how the chart loses less from it.
Standing on 9,9 against a 9. The chart splits; the stand is against 7, 10 and ace.
Using one chart for every rule set. No double after split changes four rows.
Live tables and RNG games use the same split logic, but the rules on re-splits, split aces and doubling after splits vary from game to game, so read the help screen at a live blackjack table before you play. A split doubles your stake in an instant, which matters because blackjack is not covered by the online slot stake caps. Gambling Commission rules from 17 January 2025 require at least 5 seconds per round for non-slot casino games, ban autoplay for all casino games and require net spend and time played to be shown. Setting a deposit limit is a simple way to stay in control.
Partner offers and splitting pairs
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Frequently asked questions
What pairs should you always split in blackjack?
Always split aces and 8s, whatever the dealer shows, under the 4 to 8 deck chart where the dealer stands on soft 17. Aces give two chances to make 21 with a ten-value card, while a pair of 8s is a hard 16, the worst total you can hold. Splitting both turns a poor or awkward start into two better ones. Our page on splitting aces and eights works through both in detail, including the European no-hole-card caveat.
Should you ever split 10s?
No, basic strategy never splits a pair of 10s or any two ten-value cards. Twenty is the second-best total in the game and wins most hands as it stands. Splitting it swaps that for two hands that each start on 10, which is a good start but far weaker than 20, and it doubles your stake. Some players split 10s against a dealer 5 or 6, but standing is the correct play. See hard hands in blackjack for how 20 is played.
Why should you not split 5s?
You should not split 5s because a pair of 5s is a hard 10, one of the strongest doubling hands, while a single 5 is a weak starting card. The 4 to 8 deck chart doubles 5,5 against a dealer 2 to 9 and hits it against a 10 or an ace, exactly as it plays any hard 10. Splitting would replace one promising hand with two poor ones. Our guide to when to double down lists every double, including this one.
When should you split 9s?
Split 9s against a dealer 2 to 6, 8 or 9, and stand against a 7, 10 or ace, under the 4 to 8 deck chart. Against a 7 your 18 already beats the dealer's most likely 17. Against a 10 or ace you avoid putting a second stake against a strong card. It is one of the rows players most often get wrong. Our full basic strategy guide places it alongside the other pair decisions.
Does double after split change when you should split?
Yes, it changes the plays for 2s, 3s, 4s and 6s. With double after split, split 2s and 3s against a dealer 2 to 7, 4s against a 5 or 6, and 6s against a 2 to 6. Without it, split 2s and 3s only against 4 to 7, never split 4s, and split 6s against 3 to 6. Wizard of Odds puts the cost of losing the rule at 0.14%. Our interactive strategy chart uses the double-after-split version.
How many times can you split in blackjack?
Many games allow re-splitting up to four hands, but some restrict it, and many limit or ban re-splitting aces. Lightning Blackjack and Double Exposure, for example, allow only one split. Wizard of Odds measures a no-re-split rule at 0.10% against the player, and a rule allowing aces to be re-split at 0.08% in the player's favour. The game's help screen gives the limits. The re-split entry in our glossary explains the term.
What happens if you split and get blackjack?
In most games, an ace and a ten-value card made after a split count as an ordinary 21, not a blackjack, so the hand pays even money rather than 3 to 2. It beats a dealer 20 or less and pushes against an ordinary dealer 21, while settlement against a dealer blackjack depends on whether the game uses a hole card. Check the game's help screen for the exact wording. Our answer on what happens if you split and get blackjack covers the details.
Is splitting pairs a way to beat blackjack?
No, correct splitting only reduces the house edge; the game still favours the casino. Splits often double the money in play, which makes your results swing more in both directions without changing the long-run average loss. Even with perfect play across every decision, the edge stays above zero in common rule sets. Our page on whether you can win at blackjack in the long run explains why no strategy turns it into a reliable profit.
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