Blackjack Strategy

Aria BrownStefan Weber

7 min read

Although luck is certainly involved, Blackjack is a skill based game that is known to have the lowest house edge. What that means is that practice and having a strategy can improve your odds.

Blackjack strategies are about what decisions you should make in particular situations. We are not talking about betting systems planning your stakes, but rather whether you should split, double down, or what not, depending on what cards you have in your hand.

In this Blackjack strategy guide, we'll cover the most important methods to help you master the game and improve your chances of winning.

Table of Contents

Blackjack Basic Strategy: Which Move Should I Make?

Basic blackjack strategy helps you decide what to do based on the cards in your hand and the dealer's open card. Most of it is simple mathematics based on the likelihood of you or the dealer going bust versus scoring 21.

While simple, it is a very robust strategy that covers all the card combinations you can see with recommended actions from each. And this means:

1. When to Hit or Stand - to draw another card or not
2. When to Split - to divide your two cards into separate hands
3. When to Double Down - to double the size of your initial bet

When to Hit or Stand

We start with the most basic decision in Blackjack. When to hit or stand, or in plain English, when to draw another card or not. The decision is based on the likelihood of you going bust – that is going above 21 points, on drawing a third card.

In general, the chances of going bust increase significantly with a hand of 17 or higher. Unless it's a soft 17 – that is a hand that includes an Ace, so it can be 17 or 7. The table below shows the probability of going bust if you decide to hit based on your current hand.

As you see, when your hand has 11 points, it's impossible to go bust, so you should always hit on a 11. And the dealer is most likely to bust when their card is a 5 or 6, which makes it the best starting scenario from the player's perspective.

The probability of the player winning against the dealer is 42.22%, and the probability of a loss is 49%. It's a relatively level playing field, but it's still very rare for a Tie, aka a Push or a Stand Off to occur. In that case, it's neither a win nor a loss and your bet is returned to you as is.

There are some Blackjack variants that Push on 22 instead of going bust; in these cases, do not use the basic strategy here as is, since the specific combinations and decisions in these tables are based on 21.

When to Split

Splitting is when you take the two cards you were dealt and separate them into two separate hands. This can be a useful option to increase your chances of winning.

Certain cards should never be split. For example, if you have two 10 cards, that adds up to 20, which is a really good hand and your chances of beating the dealer are high.

On the other hand, if you have two 9 cards, it adds up to 18. It's not so close to 21, but the chances of going bust are not negligible either. By splitting the 9s, you decrease the likelihood of going bust.

However, some of this also depends on what the dealer's hand might be, since you are playing against the dealer. The table below summarizes when you should split in Blackjack.

	Dealer's Up Card
Player's Hand		2	3	4	5	6	7	8	9	10	Ace
	2	SpD	SpD	Sp	Sp	Sp	Sp	H	H	H	H
	3	SpD	SpD	Sp	Sp	Sp	Sp	H	H	H	H
	4	H	H	H	SpD	SpD	H	H	H	H	H
	5	SpD	Sp	Sp	Sp	Sp	H	H	H	H	H
	6	Sp	Sp	Sp	Sp	Sp	H	H	H	H	H
	7	Sp	Sp	Sp	Sp	Sp	Sp	H	H	H	H
	8	Sp	Sp	Sp	Sp	Sp	Sp	Sp	Sp	Sp	Sp
	9	Sp	Sp	Sp	Sp	Sp	S	Sp	Sp	S	S
	Ace	Sp	Sp	Sp	Sp	Sp	Sp	Sp	Sp	Sp	Sp

Legend: H = Hit, S = Stand, Sp = Split, SpD = only split if double down is allowed / Note: 10 includes face cards

On the other hand, there are some pairs that should always be split. For example, like two 8 cards, since a hand of 16 points is so unlikely to win that it's worth taking the risk, even when the dealer has a good up card.

When to Double Down

Double down refers to doubling your bet size while drawing one more card. Even though it sounds like a risky move for advanced players at first, it is part of basic blackjack strategy because the decision is based on looking at probabilities in the dealer's hand against the probabilities in your hand. Which means that even though you are not 100% sure, you do have a pretty good idea of the likelihood on you beating the dealer.

Below is a table showing when you should double down. Note that because Doubling down will give you an extra card. Therefore you do not want to double down when your hand is 20, even though you are likely to beat the dealer. Doubling down in this situation will give you a third card, and there is a high probability that you would go bust.

	Dealer's Up Card
Player's Hand		2	3	4	5	6	7	8	9	10	Ace
	8	-	-	-	DD	DD	-	-	-	-	-
	9	DD	DD	DD	DD	DD	-	-	-	-	-
	10	DD	DD	DD	DD	DD	DD	DD	DD	-	-
	11	DD	DD	DD	DD	DD	DD	DD	DD	DD	DD
	Ace + 2	-	-	-	DD	DD	-	-	-	-	-
	Ace + 3	-	-	-	DD	DD	-	-	-	-	-
	Ace + 4	-	-	-	DD	DD	-	-	-	-	-
	Ace + 5	-	-	DD	DD	DD	-	-	-	-	-
	Ace + 6	-	DD	DD	DD	DD	-	-	-	-	-
	Ace + 7	-	DD	DD	DD	DD	-	-	-	-	-
	Ace + 8	-	-	-	-	-	-	-	-	-	-
	Ace + 9	-	-	-	-	-	-	-	-	-	-

Note: DD = Double Down / 10 includes face cards

Meanwhile, 11 is always considered a prime chance to double down. That's because your chances of drawing a 10 is high. Remember, unlike other number cards, 10 can also come from the face cards.

Although you don't have to, using double down at the right time can increase your overall edge significantly in the longer run.

Try the basic strategy at Lucky Dreams

Basic Strategy and Blackjack Variants

The basic strategy presented here is based on Classic Blackjack. Many of the concepts will still apply in other games, but it is best to adapt your strategy according to the variant you are playing. That's because, for example, whether the dealer is forced to hit or stand on a 17 directly affects their chances of a 21 in comparison to your hand.

As a general rule, always check the rules for the variant you are playing. Some games might have specific rules and give you other opportunities to split or to double down, which directly affects what you should do with each hand. Consider the basic strategy as a very general cheat sheet only.

Blackjack Games that Work With Basic Strategy

While basic strategy can be adapted for all variants, it works best in variants with rules closest to Classic Blackjack, mainly because that is what it's based on and so will require fewer adjustments. And that means basic strategy works best with these variants:

• American Blackjack
• Atlantic City Blackjack
• Vegas Strip

What these games have in common is that they all allow splitting and double down. Furthermore, the dealer's first card is always face up. These elements are considered foundational in basic strategy.

Side Bets and Insurance in Blackjack Strategy

A lot of players like to buy side bets and insurance when playing Blackjack. However, this is not part of the game's strategy in the true sense. Let's start with insurance first.

As explained in our article on Blackjack Tips, the math behind insurance does not work out. Simply put, insurance only pays when the dealer has a Blackjack from their first two cards, and under no other circumstance. And if you win, the cost of insurance eats into your overall profit. That's why pros generally advise against insurance.

As for side bets. By definition, side bets are not critical to the game itself, so they are not considered strategy. They can however be fun and you shouldn't underestimate the importance of having fun in the overall gambling experience.

Blackjack Card Counting – Thorp's Strategy

At this point, you probably understand that having at least a feeling of what cards are still in the deck will give you an advantage when playing Blackjack. This is why card counting is such a big deal in the game.

Edward Thorp, the mathematician, took things a step further and devised card counting systems to help gamblers keep track of what cards are in and out of the shoe. You don't actually count every card in these systems, but rather you develop mental tricks to keep track of things. The most famous is the Ten Count System.

Hi Lo Count

Another popular card counting system is the Hi Lo system invented by the computer scientist Harvey Dubner. It's very similar to the 10 count in that you maintain a running count as the cards are dealt. The values assigned are however different:

• 2 to 6 = +1
• 7 to 9 = 0
• 10, Face and Ace = -1

Again, if your count is high in the positives, then the probability of getting a high value card like a 10 is high. Conversely, if your count is in the negatives, the likelihood of being dealt low value cards is high.

However, casinos often add more decks to the game to increase their edge, and this directly affects the validity of your running count. That's why you want to look for the True Count, which is your Running Count divided by Decks Remaining.

For example, if you have a Running Count of -8 and 2 decks remaining, then your True Count is -4.

Edward O. Thorp is an American mathematician, professor, hedge fund manager and gambler. He became famous in the 1960s when he published his book "Beat the Dealer" on Blackjack card counting systems. In the book, he includes both the 10 Count System and Dubner's Hi Lo Count system, whom he met at a conference in 1963.

Alternative Blackjack Counting Systems

Other blackjack counting systems have developed over the years. They all aim to provide players with a more accurate picture of what cards can come up next, with greater emphasis on the True Count matching the number of decks in the game.

Below is a summary of the most important Blackjack counting systems:

	Card Value
Assigned value												Total deck value
	Hi Lo Count	1	1	1	1	1	0	0	0	-1	-1	0
	Hi Opt 2 Count	1	1	2	2	1	1	0	0	-2	0	0
	KO Count	1	1	1	1	1	1	0	0	-1	-1	4
	Zen Count	1	1	2	2	2	1	0	0	-2	-1	0
	Omega II Count	1	1	2	2	2	1	0	-1	-2	0	0
	Red Seven Count	1	1	1	1	1	0 / 1*	0	0	-1	-1	2
	Ace Five Count	0	0	0	1	0	0	0	0	0	-1	0
	Wong Halves Count	0,5	1	1	1,5	1	0,5	0	-0,5	-1	-1	0
	Ten Count	4	4	4	4	4	4	4	4	-9	4	0

* Black 7s valued at 0; Red 7s valued at 1

Below are all the Blackjack Card Counting Systems presented individually:

Hi Opt 2 Count

KO Count

Zen Count

Omega II Count

Red Seven Count

Ace Five Count

Wong Halves Count

Card counting in Online Blackjack

Before you spend too much effort mastering card counting, you should be aware that its efficiency is limited in online blackjack games. As you might have already noticed, the accuracy of card counting is highly dependent on the true count, that is the number of decks in play.

Online blackjack games typically employ an algorithm that is the digital equivalent of a continuous shuffle machine, which makes card counting impossible. However, card counting can still work in live dealer blackjack games. Look for tables where the dealer draws cards from a shoe.

Look for live dealer blackjack games where the dealer draws cards from a shoe.MoreLess

Go to Just Casino and play Live Blackjack

Blackjack Strategies and Money Management

Strategies and card counting can give you a much better idea of what cards might be dealt next so you can make the right decisions to improve your odds over the house edge. However, these are all based on probabilities, which means there can be no guarantee. There is still an important element of luck in, and it is this random element that makes the game fair.

This is why it's good to have some sort of system to keep track of your money flow in your bankroll. Blackjack systems help you decide on the size of your bet depending on certain win loss events. Most importantly, you should know what your own personal loss limit is before going in. This will help you stay in control even in the worst case scenario.

Blackjack Strategies FAQ

1. What is basic strategy?
2. Is card counting illegal?
3. Does card counting work at online casinos?
4. Which blackjack strategy is best?
5. How can I use Blackjack strategy when playing?

1. What is basic strategy?

Basic strategy in Blackjack refers to the decisions you should make given the cards in your hand versus what the dealer's open card is. For example, if you have two 10 cards, you should always stand because the chances of going bust with a hit are high, while simultaneously you have a good chance at beating the dealer since you are very close to 21. Basic strategy is based on simple but rigorous mathematics that give you probabilities on you going bust, versus the dealer going bust.

2. Is card counting illegal?

Card counting is not illegal. However, since casinos are private businesses, they have a right to ask any person on their grounds to leave for whatever reason. And that is what happens when the pit boss even suspects someone is card counting. However, this obviously doesn't apply at online casinos or if you're playing at home with friends.

3. Does card counting work at online casinos?

If you want to use card counting in online blackjack games, we suggest picking a game from the live casino section. Unlike software based games, you can see how and when card shuffling happens so you know how to maintain the true count that is critical to the success of most card counting systems.

4. Which blackjack strategy is best?

This depends somewhat on your own experience. We suggest that beginners start with basic strategy because once you understand the basics, it's easy to apply. Card counting on the other hand requires a high degree of concentration and may have limited application with different card shuffling measures.

5. How can I use Blackjack strategy when playing?

You can print out the strategy tables on this page, and use them as a cheat sheet when playing online games. We recommend RNG blackjack games that you can play for free online so you can have unlimited practice. While card counting doesn't work well with RNG games, basic strategy always works so it's good to master it.

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I am trained as a tax consultant, mostly because my father insisted that I get a normal job. Luckily, I listened to my heart and followed my passion in writing. Today I work as an online editor while traveling the world, which is why I'm rarely in my hometown, Toronto. By pure chance, I discovered the online casino review industry about ten years ago, and I have been testing and reviewing gambling sites since then. Personally, I prefer Blackjack and Poker games. I think the skills and strategies involved make them much more interesting than slots.

I'm lucky enough to have found both my job and my calling on the internet. As the online marketing manager for a major sportsbook, I began in the online gambling business over a decade ago. The business has been good to me and I love the dynamics of the industry. A blackjack enthusiast myself, I try to provide articles that combine practicalities with the strategic elegance of the game in a way that both rookies and experienced players can appreciate. And when I can, I like to spend my free time on live streaming platforms such as Twitch and Kick.