When to split in blackjack

How splitting works

A split creates two separate hands and normally requires a second stake equal to the first. Each hand receives another card and is then played under the table’s split rules.

Common pair decisions

Under the default S17 chart, split aces and 8s, keep 10s together and play 5s as hard 10. Split 9s against 2 through 6, 8 or 9; stand against 7, 10 or an ace.

Small pairs depend on the dealer’s card: 2,2, 3,3 and 7,7 split against 2 through 7, 6,6 against 2 through 6, and 4,4 only against 5 or 6 with double after split.

Why double after split matters

With 4,4 against a dealer 5 in the default multi-deck chart, split when DAS is allowed. Without DAS, hit. The recommended split depends on what can happen after it.

Split aces and limits

Many games allow only one additional card on a split ace. Resplitting rules vary. A ten-value card after splitting aces is usually an ordinary 21, not a natural blackjack. Follow the posted table rules described in blackjack rules.

Blackjack pair splitting chart

Use this table before adding an eligible pair into a hard or soft total. It assumes the default 4–8 deck S17 rules, double after split and late surrender. P = split, H = hit, S = stand, Dh = double otherwise hit. Changing DAS can change small-pair decisions.

Why you normally keep tens together

Two tens already make hard 20. Under the basic strategy used here, stand on that strong total instead of paying for two new hands. Two 5s are played as hard 10, so check the double recommendation rather than splitting.

Always check the pair row for aces and 8s. The common “split aces and eights” reminder applies to the default S17 rules, but H17 with surrender can add exceptions. If splitting is prohibited, use the hard or soft total and the actions the table actually allows.