When Should You Split in Blackjack? The Ultimate Player’s Guide

If you’ve ever sat at a blackjack table and been dealt a pair – like two 8s or two 9s – you’ve probably faced one of the most important (and misunderstood) decisions in the game: whether to split, or not to split.

Knowing when to correctly split, from a mathematical perspective, can make a major difference in your long-term profit. It can also improve your odds dramatically in the short term, too. Split incorrectly, however, and you can end up burning through chips, too!

Before you even begin playing blackjack, it’s worth understanding that the game’s not just all luck. It’s a mixture of probability, discipline, timing – and mathematics. And, thankfully, it’s possible to follow a “best strategy” which shows you exactly what move to make depending on your cards, and the dealer’s card.

So, in today’s guide, we’re going to show you exactly when you should split in blackjack – and when it should be avoided. So, no matter whether you’re playing at one of the online casinos recommended on GamesHub, or heading to your local land-based casino, you’ll know what to do – and when to do it!

The Basics of Splitting in Blackjack

Splitting is a special type of move in blackjack that allows you to, essentially, turn one hand into two hands when you’re dealt a pair. After placing an equal-sized bet on the second hand, the dealer separates your two cards, and you continue playing each hand individually – as though they were their own hand entirely.

Now, most online and land-based casinos allow you to split any pair, although there are some rare exceptions to this. Just because you can, however, doesn’t mean you should – as you’ll see from the remainder of this guide.

The Golden Rule: Always Split Aces and Eights

If you only remember one rule from this article, make it this:

• You should always split Aces and Eights. No matter what the dealer’s card is, no matter your stake size, the mathematics is always in your favour here.

Why You Should Split Aces

When you’re dealt two Aces, you have a total of 12 (or 2), neither of which is particularly strong. However, if you split then, each Ace becomes the foundation of a (potentially) very strong hand. Any 10, Jack, Queen, or King can make you a non-blackjack 21 instantly. Even drawing a 9 or 10 puts you at a high chance of winning the hand.

Note: Most casinos only allow you to receive one additional card when you split Aces, but the maths still works in your favour.

Why You Should Split Eights

A pair of 8s adds up to 16, which is statistically the worst hand in blackjack. Splitting gives you a much better chance of winning, as each 8 can become 18, 19, or even 21 quite easily depending on the next card drawn. Standing on 16 is nearly always a losing move, and hitting risks busting – so no matter what the dealer holds, splitting 8s is always your best move, mathematically.

When You Should Never Split

Just as there are golden rules for splitting, there are blackjack hands that you should also never split. Moves that may look tempting, but are mathematically wrong.

Never Split Tens or Face Cards

A total of 20 is always a very, very strong hand. The odds of improving it are practically zero, so splitting tens only weakens your position. Many beginners, however, incorrectly choose to split tens or face cards when the dealer shows a weak card (like a 4, 5, or 6) thinking it’s an “easy way to double their winnings.” In reality, however, it’s one of the quickest ways to actually lose your cash.

Never Split Fives

Two 5s make 10, which is a fairly strong hand. Even when the dealer shows an Ace or a picture card themselves, you’ll still pull a 10 or picture roughly 50% of the time, giving you fairly good odds. In fact, a starting hand of ten is usually a double-down – but that’s a topic for another guide.

Never Split Fours

Unlike a pair of 5s, a pair of 4s isn’t quite as favourable, giving you a total of 8. However, splitting doesn’t help much, either, as getting a 4 as a starting card is also a pretty bad position to be in. There are some cases where you may consider doubling an 8 – if the dealer shows a 5 or 6, for example – but again, that’s a topic we cover here: What does Double Down mean in Blackjack?

When Splitting Depends on the Dealer’s Card

So far, we’ve covered Golden rules; situations where you should always split or always avoid splitting. However, there are also situations that depend on what card the dealer holds before determining whether you should split or not.

Below, we’ll look at some of the most common pairs, and how to handle them.

Pair of Twos or Threes

In general, you should always split if the dealer shows 4, 5, 6, or 7. The dealer is quite vulnerable in this position, so you should try to play aggressively. However, if the dealer shows an 8 or above, you should not split, and hit, instead.

Pair of Sixes

If you’re dealt a pair of 6s, you should always split if the dealer shows a 2, 3, 4, 5, or 6. If the dealer shows a 7 or higher, you should simply hit.

Pair of Sevens

If you’re dealt a pair of 7s, you should split if the dealer shows a 2, 3, 4, 5, 6, or 7. This generally puts you in a fairly strong position – at least roughly 50/50. If the dealer shows an 8 or higher, however, you should hit.

Pair of Nines

Pairs of 9s can be slightly more tricky, as a starting hand of 18 is already quite strong. You should, however, split if the dealer shows a 2, 3, 4, 5, or 6, or if they show an 8 or a 9.

This one can be quite confusing for players, as many think: “why not split against a 7?” The truth is, a starting hand of 18 puts you in a favourable outcome when the dealer shows a 7, as it’s likely they will draw 17 – resulting in you winning. A pair of 9s should always be stood against a dealer’s 7, 10, or Ace.

Common Mistakes to Avoid When Splitting in Blackjack

While it’s good to know when to split – and when to avoid splitting – in blackjack, experienced players can still make mistakes, especially when under pressure. Here’s some of the most common mistakes we see players making while playing online blackjack in NZ, or in land-based casinos – and how to avoid making them yourself:

1. Ignoring the Dealer’s Card: Splitting automatically without checking the dealer’s upcard is a big no-no, unless you’re dealt a pair of 8s or Aces, as discussed.
2. Chasing Losses: When you’re in the midst of a losing session, it can be tempting to split to simply give yourself more chances to try and win your losses back. However, this more-often-than-not leads to poor decision making, and can end up resulting in further losses.
3. Not Understanding Table Rules: Some casinos allow you to re-split pairs, or double after splits – while others don’t. Always understand the rules, as this affects the basic strategy rules you should follow.
4. Forgetting Bankroll Management: Remember that splitting, while appealing in many situations, also doubles your stake. If you’re already losing, you may want to consider reducing your initial stake slightly.

Splitting in Blackjack: Final Thoughts

Knowing when to split in blackjack may seem complex, at first, but learning a bit about what it actually means – when to do it – and when to avoid it – is what helps to separate casual players from consistent winners. Believe it or not, splitting is not about luck or “gut feeling” – it’s about understanding the maths behind the game itself, and applying it without second-guessing yourself.

When you split the right pairs (especially Aces and Eights) and avoid the most common traps (like splitting Tens or Fives that may look appealing, at first), you reduce the house odds significantly – the point where, in some cases, the casino house edge is almost non-existent.

So, remember; next time you sit down at a table or play at the best online blackjack sites in NZ, think about whether it’s really advisable to split a pair – or whether you’re making an impulsive decision.

Last updated: 10/11/2025