Why Split Aces and 8s in Blackjack?

These are the only two pairs basic strategy splits against every dealer upcard, no exceptions worth making. Here's why both are automatic.

Short answer

Split both. A pair of Aces is split because keeping them together caps the hand at a weak 12. A pair of 8s is split because playing them as a hard 16 — the single worst total in blackjack — is worse than playing two hands starting from 8. Both hold against essentially every dealer upcard, which is rare among pair decisions.

Why Aces are split

A pair of Aces played together is stuck as a hard or soft 12 — a weak total either way, since one Ace has to count as 1. Splitting gives two separate hands, each starting with an Ace and a strong chance of drawing into a total near 21. Most tables only allow one card per hand after splitting Aces, which caps the upside slightly, but it doesn't change the conclusion: splitting Aces is correct against every dealer upcard.

Why 8s are split

A pair of 8s is a hard 16 — too high to hit comfortably, too low to stand on with any confidence. Splitting turns that one bad hand into two hands that each start at 8, a meaningfully better starting point than 16 against almost any dealer upcard, including strong ones like 9 or 10. The only exception: against a dealer 10 or Ace when late surrender is available, surrendering the pair outright can be slightly better than splitting.

What makes these two different from other pairs

Most pair decisions depend heavily on the dealer's upcard — 9s split against some cards and stand against others; 4s only split with Double After Split available. Aces and 8s are the exceptions: the starting hand they'd otherwise be stuck with (12 and 16) is bad enough, and the split alternative good enough, that the dealer's upcard barely moves the conclusion. See the full basic strategy chart for every other pair, or read Splitting Pairs for the complete reasoning, including why 10s are the mirror-image case that's never split.

Practice it

The trainer shows the probability and expected value behind splitting Aces and 8s as you play, so you can see exactly how much value the split adds over keeping the pair together.

Practice Split Decisions