Knowing when to split in blackjack comes down to two fixed rules and one table. Split aces and 8s against anything; never split 5s and 10s. The other six pairs (2s, 3s, 4s, 6s, 7s and 9s) depend on the dealer's upcard and on whether the table lets you double after a split.
On this page
The split chart: every pair, every dealer card
Read across from your pair, down from the dealer's upcard.
| 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 | – | – | – | – | – | – | – | – | – | – |
| 9,9 | P | P | P | P | P | – | P | P | – | – |
| 8,8 | P | P | P | P | P | P | P | P | P | P |
| 7,7 | P | P | P | P | P | P | – | – | – | – |
| 6,6 | P* | P | P | P | P | – | – | – | – | – |
| 5,5 | – | – | – | – | – | – | – | – | – | – |
| 4,4 | – | – | – | P* | P* | – | – | – | – | – |
| 3,3 | P* | P* | P | P | P | P | – | – | – | – |
| 2,2 | P* | P* | P | P | P | P | – | – | – | – |
P = split. P* = split only if the table allows doubling after a split; otherwise play the hand by its total. – = do not split. The chart is the four-to-eight-deck strategy with the dealer standing on soft 17, as published by the Wizard of Odds. At an H17 table the pair column does not change, except that 8,8 against an ace is surrendered where surrender is offered. For the hands you play by their total, use our full basic strategy chart.
Why each pair is played this way
Aces. Together they are a soft 12. Split, each ace starts a hand on 11, and a ten-value card makes 21. Most tables give one card to each split ace; that the right to draw more is priced as a bonus rule (below) tells you one card is the norm.
8s. Sixteen is the worst total in the game: too high to hit comfortably, too low to win by standing. Two hands starting on 8 lose less than one 16, even against a ten.
10s. Twenty wins most of the hands it is dealt. Splitting turns it into two hands starting on 10, each worse than the hand you broke up.
5s. Ten is a doubling hand. Split, you get two hands starting on 5, which is about the weakest start there is.
9s. Eighteen beats a dealer 17 and loses to a dealer 19. Against a 7, the dealer often finishes on 17, so you stand. Against an 8 or 9, the dealer often makes 18 or 19, so two hands starting on 9 do better.
2s, 3s, 4s, 6s and 7s. These are weak hands. Splitting them puts more money on the table when the dealer is likely to bust, which is why the P cells cluster under the dealer's 2 to 7. Doubling after a split matters here: a split 2 or 3 often draws to 10 or 11, and without the right to double that hand, some of these splits stop paying.
What the split rules are worth
How you split in blackjack is your decision; how far you may split is the table's, and those rules move the house edge. The formula is the same as for every rule on the site:
edge of your table = base edge + sum of rule changes, and expected cost = hands × stake × edge.
| Split rule | Change to the player's return |
|---|---|
| Double after split not allowed | −0.14% |
| No resplitting: one split per hand | −0.10% |
| Split to three hands instead of four | −0.01% |
| Aces may not be split | −0.18% |
| Lose split bets to a dealer blackjack (no hole card) | −0.03% |
| Resplitting aces allowed | +0.08% |
| Double or stand after splitting aces | +0.08% |
| Draw more than one card to a split ace | +0.19% |
| No splitting at all | −0.57% |
These are the Wizard of Odds figures against a baseline of eight decks, dealer stands on soft 17, doubling on any two cards, doubling after a split and splitting to four hands. Doubling and splitting are close cousins at the table; our house edge page prices the doubling rules.
Five tables, recalculated
Start from about 0.45%, the house edge we use for eight decks, S17, doubling after a split and a 3:2 blackjack, with resplits to four hands and one card per split ace.
| Table | Split rules | House edge | 1,000 hands at $10 | 1,000 hands at $25 |
|---|---|---|---|---|
| 1 | baseline | about 0.45% | $45 | $112.50 |
| 2 | no double after split | 0.45 + 0.14 ≈ 0.59% | $59 | $147.50 |
| 3 | no double after split, no resplit | 0.45 + 0.14 + 0.10 ≈ 0.69% | $69 | $172.50 |
| 4 | resplit aces allowed | 0.45 − 0.08 ≈ 0.37% | $37 | $92.50 |
| 5 | resplit and draw to split aces | 0.45 − 0.08 − 0.19 ≈ 0.18% | $18 | $45 |
Table 5 is rare; it is there to show the scale. The usual choice is between tables 1 and 3, which differ by about 0.24 points: $24 for every $10,000 you stake.
How often do you get the chance to split in blackjack? After your first card, 31 of the remaining 415 cards in an eight-deck shoe match its rank: 31 ÷ 415 ≈ 7.5%, or about one hand in 13. Over 1,000 hands that is around 75 pairs, about 23 of them aces or 8s that you split every time.
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What changes the result most
Five things decide what a split in blackjack is worth to you, in this order:
- Splitting at all, and splitting right. A player who never splits gives up about 0.57 points: more than every split rule on the table put together. Breaking up 10s or refusing to split 8s is where most of that leaks.
- Splitting aces. Losing the right to split them costs 0.18 points. Nearly every table allows it; check.
- Double after split. 0.14 points, and it changes seven cells in the chart.
- Resplitting. 0.10 points for being allowed to split again; resplitting aces is a separate, rarer bonus.
- The hole card. Without a peek, a dealer blackjack also takes your split bets: 0.03 points. Our dealer rules page covers the peek in full.
Deck count and the soft 17 rule barely touch the split decisions. The payout on a natural matters far more to the overall edge than any split line; see 3:2 vs 6:5.
A checklist before you split in blackjack
- Read the info screen: double after split, number of splits, and the rules for split aces.
- Split aces and 8s without a second thought.
- Never split 10s, whatever the last few hands looked like.
- With no double after split, drop the P* cells: 2s and 3s against 2 or 3, 4s against 5 or 6, 6s against 2.
- At an H17 table with surrender, surrender 8,8 against an ace.
- Keep a split chart open if you need it; an online table cannot see your screen.
Each split doubles the money on that round, so size your stake for it: a $10 hand split twice is $30 in play. Ignition and Cafe Casino both list many RNG blackjack versions, so the split lines are worth comparing game by game; see our Ignition and Cafe Casino reviews.
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The score counts what each casino publishes about licence, ID checks and limits, not how much we like the lobby.
Questions and answers
Should you always split aces and 8s?
Yes, against every dealer card on a four- to eight-deck table where the dealer stands on soft 17. The one change: where the dealer hits soft 17 and surrender is offered, a pair of 8s against an ace is surrendered.
Should you ever split 10s?
Not if you play basic strategy. A 20 wins most hands it is dealt; splitting it swaps one strong hand for two that start on 10.
What does double after split mean?
You may double down on a hand made by splitting, for example a 2 that draws a 9 to make 11. The rule is worth about 0.14 points, and without it you split 2s, 3s, 4s and 6s less often.
How many times can you split in blackjack?
That is set by the table. The common baseline is up to four hands; a table that stops at one split costs you about 0.10 points, and one that stops at three hands costs about 0.01.
When should you split 9s?
Against a dealer 2 to 6, 8 or 9. Stand on 18 against a 7, a ten-value card or an ace.