Blackjack Pair Splitting

Splitting pairs has massive potential for maximizing your profits at the blackjack table. This move can be just as lucrative as doubling down, but unfortunately, the vast majority of recreational players find themselves in a quandary when they are dealt a pair.

Some split all pairs regardless of the rank of the two cards, while others prefer not to split at all. There is also a third group of unskilled players who follow their gut and split pairs at random. What they tend to forget is that blackjack is a purely mathematical game, and, as such, it does not allow them to make intuitive decisions as in other card games like poker.

The irony is that splitting pairs was introduced not only to make the game more exciting but also to reduce the house edge. In fact, the house advantage increases by nearly 0.60% if players are prohibited from splitting pairs altogether.

Instead of taking advantage of the splitting option to increase their profits, many blackjack players make awful splitting decisions, which only end up making money for the house. The following article aims to clarify when and why pair splitting is the optimal playing decision and when players should refrain from it.

Pair Splitting: How Does It Work?

The concept of pair splitting is simple to grasp: when players are dealt a pair of cards of equal value, like J-J, 4-4, or A-A, they have the option to split and play them as two separate hands.

For instance, suppose your original hand consists of a pair of 7s and you have initially wagered $10 on it. You can play your hand as a total of 14 and hit or stand, depending on the dealer’s upcard, but you can also decide to split the 7s into two separate hands. If you choose the latter, you need to post a second bet in the same amount as your original one, so your total action increases to $20.

Keep in mind that you cannot announce your decision to split verbally only; you must also indicate it with a hand signal, which in this case is to form a V shape with your index and middle fingers and tap the felt next to your betting circle.

The chips for the extra bet should never be placed on top of your original wager; instead, position them next to your initial stack of chips. The dealer will then separate the 7s into two hands and draw one extra card on each 7. The two hands are then played one after the other, and players have a choice from the standard playing decisions. Should they receive another pair, they typically have the option to resplit.

Rule Variations Pertaining to Pair Splitting

The tricky thing about pair splitting is that the rules governing this move may vary depending on the casino where you are playing. In most establishments and online blackjack variations, players are allowed to resplit until they form up to four separate hands.

The resplitting of Aces is prohibited at many tables, which gives the house edge a boost of roughly 0.08%. Note that split Aces receive only one additional card, and players are not allowed to hit afterward. This peculiarity of the rules increases the house edge by around 0.19%. There are also casinos that allow you to split ten-value cards, but only if they are of the same denomination, like a pair of 10s or a pair of Jacks.

In most cases, doubling down after splitting (DAS) is allowed, which enables you to increase your action to up to eight bets (i.e., if you have resplit to four hands and doubled on each one). Another important thing to keep in mind is that when you split a pair of Aces and draw a ten-value card next to your Ace, the hand is not considered a blackjack. It is counted as a regular total of 21, so you receive even money if you win. DAS is a very profitable rule for the blackjack player, and its absence (NDAS) is quite detrimental, taking away around 0.14% from your advantage.

How Pair Splitting Helps Blackjack Players

As we mentioned briefly in the beginning, pair splitting is very useful because it decreases the house edge by nearly 0.60%. But how does it help the player exactly? If you take a look at the basic strategy chart, you will notice that, similar to doubling down, splitting is mostly recommended when the dealer’s upcard is weak enough to justify an increase in your bets.

This is the right course of action particularly against dealer upcards such as 4, 5, 6, and 7, but whether or not this is the optimal move also depends on which pair you are holding. Splitting helps players in several ways.

First, it enables you to generate more profit on average over the long run because you place more money on the felt against a weak dealer who is more likely to lose.

Second, splitting enables you to minimize your average losses over the long term, which is just as important.

Finally, this playing decision gives you the opportunity to turn a bad starting hand into a good one, potentially increasing your chances of winning the round.

Here are several examples of how pair splitting helps you win more, lose less, and transform a bad hand into a good one.

Pair Splitting Allows You to Maximize Your Profits

Our first example involves a hypothetical situation where you are dealt paired 9s against a dealer showing a 6 at a multiple-deck table where the dealer is required to stand on soft 17 and you can split to up to four hands. If you choose to stand on your total of 18, you will win 64 out of every 100 hands on average and lose the other 36 times.

The odds are clearly in your favor in this case. When you flat bet with a base unit of $10, you can expect to generate profits of $2.80 per hand on average (640 − 360 = 280 / 100 = 2.80), provided that you always choose to stand on your paired 9s against a dealer whose upcard is a 6.

The interesting thing here is that splitting this pair decreases your chances of winning by four percentage points, to 60%, but increases the profits you generate. You win only 60 out of every hundred hands on average and lose the other 40 times. Thus, your average profit when you split this pair against the 6 will be equal to (600 − 400) * 2 = 200 * 2 = 400 / 100 = $4. This corresponds to a $120 increase in your profits for every hundred split hands with a base unit of $10.

Pair Splitting Helps You Minimize Your Losses

Splitting clearly boosts your winnings, but it also helps you reduce your losses from negative-expectation bets. For example, suppose the dealer starts their hand with a deuce and you bet $10, only to be dealt a pair of 7s for a poor total of hard 14. This hand has more than a 50% probability of busting.

Let’s see what happens if you decide to consistently stand on your paired 7s with a flat bet of $10. The odds swing in favor of the house this time, as your expected win rate drops to 36 out of every hundred hands. Therefore, you lose 64 out of every hundred hands, which corresponds to an average expected loss per hand of $2.80. But what if you split your pair of 7s?

Splitting improves your likelihood of success because it allows you to start each of the two hands with a 7 instead of 14. Consistently making this decision will cause you to lose only 55 out of every hundred hands and win the other 45 times. It follows there is a drop in your average net losses per hand of $0.80 because (550 − 450) * 2 = 200 / 100 = 2 and $2.80 − $2 = $0.80.

Splitting Helps You Improve Your Hand Sometimes

One of the most rewarding situations at the blackjack table is when a player starts a round with a poor two-card total but improves it after a split. Let’s examine a third example where you bet $10 and again receive paired 7s, but this time the dealer exposes a 6 instead of a deuce. Many rookie players choose to stand. Yet this is far from a good decision, and here is why.

When you choose to stand with 7s against a weak dealer showing a 6, you will win an average of 42 out of every hundred hands and lose the other 58. You are again facing a negative expectation, and your long-term loss per hand amounts to $1.60.

The option of splitting gives you the chance to start each of the two hands with a 7. This is a significant improvement in the odds because now you are facing a positive expectation in the long run. When you split your 7s against a 6 consistently, you end up winning 52 out of every hundred hands and lose only 48 on average. This accounts for net profits of ($520 − $480) * 2 = $40 * 2 = $80 / 100 = $0.80 per hand on average.

The Pairs You Should Never Split

Some players rely on intuition when splitting pairs, which ultimately results in losing money over the long run. In blackjack, some pairs should never be split, or at least not if basic strategy is your only weapon in the battle against the casino. Such is the case with pairs of 5s and pairs of ten-value cards.

When you start a round with a pair of 10s, you face two possible playing decisions: you either stand on your pat 20 or split the pair. Some inexperienced players tend to choose to split, especially against a dealer with a weak upcard like 5 or 6.

They justify this move by assuming they have the opportunity to win two hands instead of one when the dealer is in a breaking position with these small cards. But they are wrong because this only ends up costing them more money in the long term. Standing on pat 20 wins 78 out of every hundred hands you play on average against a dealer with a 6 who hits soft 17.

In 11 of the remaining instances, you tie with the dealer and lose in the other 11, which means standing earns you roughly $6.78 per hand (provided that you use a bet unit of $10). If you choose to split your 10s, your average expected win per round decreases to around $5.60 for both hands combined. You end up winning less money despite increasing your action when in a favorable position, which is why you should never split 10s unless you are counting cards.

The same applies to pairs of 5s: you should always refrain from splitting them if you rely solely on basic strategy at the table. A starting hand with a total of 10 puts you in a very good position. You risk ruining your hand and losing twice as much in the process.

The Pairs You Should Always Split

Basic strategy dictates that one should always split pairs of Aces and 8s, but many novices choose not to listen. Paired 8s create the worst possible total in the game, even more so if the dealer exposes a strong ten-value card.

A total of 16 should always be surrendered against a dealer’s 10, but not if it consists of two 8s. Inexperienced players often forfeit this pair in exchange for half of their bet, fearing they might end up with two bad hands instead of one and lose twice as much in a single round.

And indeed, there is no doubt that a pair of 8s against a dealer’s strong ten-value card puts you in a very bad spot, regardless of whether you choose to hit, stand, split, or surrender. You will inevitably end up losing money. However, playing two hands with a starting point of 8 causes you to incur smaller long-term losses than playing one hand with a total of 16 against a powerful dealer’s 10.

Either hitting or standing in this situation leads to winning only 23 out of every hundred hands, while the other 77 hands result in losses, excluding pushes. If you bet $10 per hand, you will end up losing an average of $540 by hitting or standing.

Splitting actually increases your chances of success with this hand. If you make this move, you win 38 out of every hundred hands on average and lose the remaining 62 times. Therefore, you incur net losses of ($240 * 2) / 100 = $480 / 100 = $4.80 per hand. There is a slight improvement, as you lose $0.60 less per hand when splitting.