When Should You Split in Blackjack? A Simple Pair-Splitting Guide
Quick answer: In the six-deck, dealer-stands-on-soft-17 (S17) game used on 0stakes, always split Aces and 8s under the stated rules, and never split 10-value pairs or 5s. The other pairs depend on the dealer's upcard. The chart below applies specifically to a game that allows double after split (DAS), permits one split only, and does not offer surrender.
Splitting means turning a pair into two separate hands by placing a second wager equal to the first. That can improve the expected value of certain pairs, but you are risking more money than you were on the original hand. It isn't a bet-doubling trick, and splitting two cards that merely total the same value does not always follow the same rule as a pair.
Blackjack split chart: six decks, S17, DAS
| Your starting pair | Split against dealer upcard | Otherwise |
|---|---|---|
| A,A | 2 through Ace | — |
| 10,10 (also J/Q/K combinations where treated as a pair) | Never | Stand on 20 |
| 9,9 | 2–6, 8–9 | Stand against 7, 10, Ace |
| 8,8 | 2 through Ace | — |
| 7,7 | 2–7 | Hit against 8–Ace |
| 6,6 | 2–6 | Hit against 7–Ace |
| 5,5 | Never | Treat as hard 10; double when appropriate, otherwise hit |
| 4,4 | 5–6 | Hit otherwise |
| 3,3 | 2–7 | Hit against 8–Ace |
| 2,2 | 2–7 | Hit against 8–Ace |
Scope matters: This is an ordinary total-dependent basic-strategy teaching chart, not a claim that every casino has identical rules. Splitting recommendations can change with deck count, whether the dealer hits soft 17, whether double-after-split is offered, surrender availability, and exact pair-hand restrictions. If you are learning another ruleset, use the chart for that particular game. Find the complete decisions in the 0stakes blackjack strategy chart.
Why split Aces?
Two Aces count as either 2 or 12 together, an awkward starting point for a single hand. Splitting gives each Ace a fresh second card and a chance to create a strong total. On the 0stakes ruleset, split Aces receive only one additional card each. An Ace plus a 10-value card after a split is generally a 21, not a natural blackjack paying 3:2. Even with those restrictions, splitting is the basic-strategy play here.
Why split 8s, even against a dealer 10?
Two 8s make hard 16, one of the least comfortable blackjack totals. Starting two hands at 8 creates better possibilities than keeping the hard 16 under these rules. You can still lose both hands, and you have to post a second wager. The recommendation is about long-run expected value, not whether splitting feels safe in a particular round.
If your bankroll cannot cover the extra wager, you cannot split at that moment. That is one reason to size your original bets with possible splits and doubles in mind.
Why you shouldn't split 10s
A pair of 10-value cards totals 20, a very strong standing hand. Splitting replaces that strong hand with two uncertain starting hands and an additional wager. A card counter playing with a demonstrated advantage may sometimes deviate from ordinary basic strategy, but beginners should not interpret that exception as general advice to split 10s.
Why 5s are different
A pair of 5s is a hard 10. Keeping the 10 offers a strong opportunity to double in the right dealer matchup. Splitting creates two hands starting with just 5, often giving up value. The correct next action depends on the dealer card and table rules, but splitting is not the basic-strategy choice in this ruleset.
A few examples you can practice
Pair of 9s vs dealer 7: Stand. An 18 is already a respectable total against a dealer 7; splitting isn't the recommended basic-strategy move.
Pair of 9s vs dealer 8: Split. Those two starting 9s have better combined expected value under the strategy model than standing on 18.
Pair of 4s vs dealer 6: Split when DAS is allowed in this ruleset. Without DAS, the decision can differ; check the chart that matches your table.
Pair of 7s vs dealer 10: Hit rather than split, even though 14 is a weak total. Splitting would put another wager at risk without improving expected value under these assumptions.
Three splitting mistakes to avoid
First, don't confuse two 10-value cards with two 5s just because both might look like obvious doubles or splits: they play very differently. Second, don't assume every table lets you resplit repeatedly or draw freely after splitting Aces. Third, don't ignore your bankroll: a $10 initial bet may quickly need another $10 to split, and potentially another $10 to double if the rules permit it.
The best way to remember the exceptions is to practice them. Open the free blackjack game or use the basic-strategy trainer and drill pairs until the choices feel natural. To understand how different bet sizes change your session, see How Long Will $100 Last Playing Blackjack?.
Frequently asked questions
Do you always split Aces and 8s?
For the six-deck S17, DAS, no-surrender rules described here, yes. Different rules and specific advanced counting situations can alter decisions.
Should you split 9s against a 7?
No. Stand on 18 in this ruleset. Split 9s against 2–6 and 8–9.
Should you split 4s against a 6?
Yes when double-after-split is permitted under the chart above. Rules without DAS require their own strategy chart.
Does splitting give you a better chance of winning?
Splitting is recommended when it improves long-run expected value under the rules, not necessarily because it increases the probability of winning both hands. You could still lose both.
What happens if you can't afford to split?
You can't place the required equal second wager. Play the original hand according to the legal options remaining and avoid treating a split decision as permission to exceed your bankroll.
0stakes is a free-play educational website. This chart is specific to the rules stated above, not a universal casino strategy.