Blackjack Theory: How To Know When To Split

min read
A blackjack game in progress.
BetMGM Dec 04, 2023, 6:19 AM

When playing live dealer blackjack, there are a number of strategies players use to try to tilt the odds in their favor. Often forgotten, splitting in blackjack remains one of the mysterious techniques in a player’s arsenal – even to experienced players. If used effectively, it can be beneficial to your game. Read on to learn how to know when to split in blackjack.

What Is Splitting in Blackjack?

Splitting in blackjack occurs when a player holds two cards of the same value, such as a 9–9. This gives individuals the option to split their current hand into two separate hands. If approved, the dealer will provide you with additional cards. In order to proceed, the player must stake an extra bet that holds the same value as their original bet. In essence, if you want to split when dealt a pair, place the same amount of chips again, and the dealer will go ahead. If you’re playing at an online casino, there is usually a button on your screen that gives you the option for splitting in online blackjack.

If you’re playing blackjack online, be sure to read the casino’s rules on splitting, as they can vary between sites. The same applies to the blackjack splitting rules at land-based casinos. Some allow splitting on certain pairs, while others allocate a certain number of times you are allowed to split. Generally, casinos will allow players to split three times.

Why Should I Split in Blackjack?

When playing blackjack, basic strategy goes a long way. Splitting, for example, is one of the most beneficial methods for the longevity of your game. Statistically, the dealer will start with a 2% house edge. For example, for every $50 you stake, you’ll lose $1. How do you reduce that? By implementing the best blackjack strategy for the situation.

Splitting in blackjack can give the player a 0.4% edge over the house, therefore increasing your chances of success. If not used, it can add 0.4% to the house’s edge. So, if the timing is right, you have the chance to tip the odds in your favor and put pressure on the dealer.

When To Split Cards in Blackjack?

In a game scenario — whether land-based or online — there are typically two situations when splitting should be called upon. One is for defensive purposes, and the other is for attacking.

Defensively, it allows players to break up a bad value pair into a better scoring opportunity. For example, if you’re holding 7–7 and the dealer has two picture cards, it means you’re holding 14 in comparison to the dealer’s 20. This puts the player in a tricky scenario due to the high probability that they will bust if they call for another card. By splitting up the pairs, you’re increasing your chances of a winning combination.

Attacking-wise, it’s a great method to get more money on the table against a weak hand. If you’re holding a 4–4 against a dealer’s 8, it suggests that the dealer is more likely to bust on the following card. By splitting, you have the chance to create better hands and increase the round’s profitability. If you’re dealt a pair, and the dealer is on the back foot, it’s usually a good indicator to utilize a split strategy.

However, if you want to know when to split and double down in blackjack, it’s also important to remember that risks are involved regardless of the cards shown. In gambling, nothing is certain, so you should only stake what you’re able to lose. If you don’t succeed, remember that it happens to everyone (experienced and beginners alike), so try not to let it mentally affect you. 

Which Pairs You Should and Shouldn’t Split in Blackjack Games

If you’re dealt a pair, it doesn’t mean you should automatically split. If you look at things from a mathematical perspective, probability dictates that there are certain pairs that are more likely to give you a favorable outcome if you split. There are also pairs that certain pairs that you should never split, and some when the decision to split or not depends on what the dealer’s up-card is. Keep in mind that these aren’t hard and fast rules that will guarantee a win every time; they are just helpful guidelines based on probability at the blackjack table. 

Pairs to Always Split in Blackjack

    • Aces: The advantage of aces is that they double up as an 11 or 1. This means a pair of aces gives you ample opportunity to create a winning combination.
    • Eights: Experienced players regard 16 as the worst hand in the game due to it not being a strong enough value, combined with its high chance of busting on the next hit. It only takes a 5 to bust a pair of 8s. By splitting the pair of 8s, you’re giving yourself a better chance for success.

Pairs You Should Never Split in Blackjack

  • Fours: With a pair of 4s, the most you can get is 19, a high total. Moreover, if you’re holding a 4–4, there’s no chance you will bust on the next hit. So, you may as well play out the round with a pair of 4s, as your chances of going over 21 are slim.
  • Fives: Like a pair of 4s, holding a 5–5 means you cannot go bust on the next hit. Holding an accumulation of 10 from your first two cards is the best start to a round. This means it takes an ace, 9, 10, or any picture card to put you in a strong position — a lot more possibilities than other hands.
  • Tens: If you’re dealt a pair of 10s, you should remain in that position. Having 20 is the second-strongest number in the game, so why change that?

Splitting Based on the Dealer’s Up-Card

Option 1

If you have pairs of 2s, 3s, or 7s, and the dealer’s up-card is between 2 to 7 (inclusive), it is usually best to split. With these hands, the phrase “there’s nowhere to go but up” comes to mind. These are some of the lowest-ranking blackjack hands, all of which have the potential to bust in one or two hits. So, if you split them, probability suggests that your hand is more likely to improve.

Option 2

If the dealer’s up-card is between 2 to 6 (inclusive), 8, or 9, and you have a pair of 9s, whether to split or not is a coin toss. Standing on 18 can be anxiety-inducing — It is still a beatable hand, but unless you’re a master card counter and you know for sure which card will be dealt next, it’s never a good idea to hit on such a high value. So, you just need to play the percentage game to see which odds you feel more comfortable with.

Option 3

If the dealer’s up-card is 2 to 6 (inclusive) and you have a pair of 6s, splitting is usually a good move in terms of probability. If you split when the dealer has an up-card in this range, you could still get a ten, which would put you at an advantage over the dealer who could likely bust.

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Our BetMGM editors and authors are sports experts with a wealth of knowledge of the sports industry at all levels. Their coverage includes sports news, previews and predictions, fun facts, and betting.

Our BetMGM editors and authors are sports experts with a wealth of knowledge of the sports industry at all levels. Their coverage includes sports news, previews and predictions, fun facts, and betting.