Best and Worst Times to Split and Double Down in Blackjack

Double Down Blackjack-Man w/Cash

What makes any casino game interesting is when the play suddenly changes.

A basic round of blackjack involves players deciding whether to hit or stand on the cards they are dealt. It’s fun to beat the dealer, to be sure, but there’s more to the game than that.

Some players feel all the challenge is in counting cards. And given how casinos love to frustrate card counters by changing or shuffling shoes, card counting may be the most challenging strategy of all.

Whether you count cards or not, the moment the dealer hits you with a pair of aces or 8s, you should know to split right away.

But what if you’re dealt 10 points? You have two 5s in your hand and conventional blackjack strategy says to “never split 5s.” Some adventurous players do it anyway. 10 points is a strong hand, and the next card you’re dealt could be an ace or 10-point card.

You’d have to be insane to split 5s. I’d rather double down on a pair of 5s if I’m feeling adventurous.

So, what are the best hands to split or double down when playing blackjack for real money? And are there times when going against conventional wisdom is less risky? Find out below.

When to Split 5s – If Ever

I’ll start with the insane situation. I cannot think of a reasonable rationale for splitting 5s, but a friend once asked me to imagine a scenario where it’s at least not as stupid an idea as it sounds.

Assuming you’re counting cards and the casino is in a laissez-faire mood about shuffling the shoe, you’d be okay to split 5s if you’re really confident you have a lot of low value cards left.

To move a 5 card into winning territory, follow it with 12 or more points. That could be two 6s, a 5 and 7, a 4 and 8, a 3 and 9, or a 10 and 2. If the following cards are really bad, you could do this with four 3s, three 4s, two 5s and a 2, and other unlikely combinations.

It seems like there are a lot of possible combinations to play with here. Splitting 5s really means you’re playing two 5-point hands. Imagine what you’d have to do if your hand begins with a 2 and 3. You have no choice but to hit.

If the next card is an ace, you’re sitting with either 6 or 16. You must hit and hope for an ace or 2-5 card.

I have a friend who calls this “climbing out of the hole.” You’re clawing your way up into winning territory. When I start with such a weak hand, it feels like I have to take three or four hits to resolve the hand.

Unless you just want to risk your wager and chew through cards, I can’t think of a reason to split 5s. But if you forced me to do it at least once, I would only do it if I believed there were a lot of low-value cards left.

Who wouldn’t want to beat the odds, right?

When to Double Down on 5s

Assuming your sanity doesn’t leave you in the middle of the game, is it a good idea to double down on a pair of 5s?

Our card-counting friends might say it’s worth the risk if you’re feeling adventurous and are confident the next card will be a 7 or better. Standing on a soft 17 is better than guessing whether you’ve got more low cards coming. But don’t make this decision in a vacuum.

When you’re dealt a pair of 5s, conventional strategy says if the dealer’s up card is anything from 2 through 9, you should double down.

Basic Strategy for Doubling Down

Most basic strategy guides on doubling down fail to keep it simple. Doubling down doesn’t work the same way for everyone. When a strategy is based on assumed table rules, you should really think it over carefully.

If a strategy guide says, “this works when you have six decks in the shoe,” or “when the dealer must stand on soft 17,” that means the strategy may not work as well for you in other situations.

The “basic” part of basic strategy begins with knowing what rules you’re playing under. If you’re in a highly coveted single deck game, put that eight-deck strategy card aside and vice versa.

The casino may restrict doubling down to high-value hands of 9 or higher. To keep it simple, if you’re playing by these rules, only double down on an ace+7 hand. A more experienced player may feel up to the challenge of calculating the odds for other combinations.

If the casino allows you to double down on any hand, your safest strategy is to double down on hard 11 against any dealer up card and a hard 10 if the dealer’s showing a 2 through 9. There are other guidelines for doubling down, but they assume certain rules are in play.

Give yourself time to learn the game.

When Is It Best to Double Down With an Ace?

Everyone should know to split aces in blackjack. But when should you double down if you’re holding an ace?

When you double down, you only get one more card. When this strategy pays off, you only need one more card.

There are two things to consider:

  1. What’s your second card’s value?
  2. What’s the dealer’s up card value?

If you were dealt an 8 or higher card with your ace, don’t double down. Period. You’re sitting on 19 or better. If you have an ace and you’re sitting on 18, you might be able to get away with doubling down if the dealer’s up card is a 3, 4, 5, or 6.

The lower your second card is, the more likely you can get away with doubling down. But the dealer’s up card should play into your decision. If the dealer is showing a deuce or anything better than a 6, don’t double down.

Should You Always Split 8s?

Basic blackjack strategy says 8s are a safe and wise split. It’s hard to go wrong with splitting 8s. The math says this works out well in the long run.


So, there you are with a pair of 8s and you split, and the dealer hits you with a 5. You kick yourself for walking away from an easy 21.

If you’re playing blackjack, there are too many hands in your future to justify second-guessing yourself. Learn from each situation as you go along, but don’t expect to become a blackjack genius overnight.

If you’re counting cards and you believe there are a lot of low value cards left in the deck, splitting 8s may not be the wisest move. You only need a 2 through 5. That’s a narrow range of cards, but if you’re sure more of the higher value cards have been played, your chances of surviving are better.

A simpler way to make the call is to look at the dealer’s up card. Some people won’t split 8s if the dealer is showing a 9 or 10.

The simplest strategy is to always split your 8s. When you gain more experience, you may cut some losses by judiciously not splitting 8s.


Basic strategy should simplify your decision-making as much as possible. Some basic strategy guides don’t simplify things enough.

Keep in mind though, the simpler your strategy, the more missed opportunities you’ll have. And if you don’t recognize those missed opportunities, you’re probably not ready to use the exceptions to basic strategy.

As you gain experience and see what could have been done with your hand, go back and study the exceptions in basic strategy guides. Wait until you’re truly ready to play a more challenging game.