Counting Cards in Blackjack

Counting cards in blackjack is one of the only ways to get an edge over the casino--i.e., it's one way of playing blackjack profitably. The way that casinos make their money is by setting up the rules of each game in such a manner that they have an edge over the player. Since the composition of a deck of cards changes as each card is dealt, you're able to raise the amount you're betting when the odds are in your favor, and lower the amount you're betting when the odds are against you. Try blackjack for money for yourself, and you'll quickly see why this is true.

That doesn't mean it's easy. If it were easy, everyone would be doing it, and the casinos would have no choice but to change the rules or eliminate the game. They're never going to offer a game where the player has a consistent advantage, just like a grocery store is never going to sell groceries at a consistent loss. Businesses are motivated by profit.

Why isn't it easy to get an advantage this way? There are multiple reasons. One is that it requires a lot of practice and skill to gain a small edge, even at bitcoin blackjack at So you have to be smart and dedicated if you want to succeed, and you also need a sufficient bankroll to be able to play long enough for your small long-term advantage to kick in. One of the other reasons is that casino don't like card counters. They'll kick you out of the game or out of the casino if they think you're doing it. Another tactic they'll use is to shuffle every hand in order to eliminate the possibility that you'll get an edge.

Basic Strategy and the House Edge

Beat the Dealer - The First Book about Counting CardsBefore learning this particular advantage gambling technique, you have to learn something called "basic strategy". This will come in handy even if you decide that counting cards isn't for you. Basic strategy is the mathematically correct play for every possible hand in blackjack. Before you can tilt the odds in your favor, you have to be able to reduce the house's mathematical dominance over you. Memorizing and then using basic strategy is how you do this. The house edge in blackjack for a player who just guesses at how to play is around 4%. Basic strategy reduces that to 0.5% or so.

The house edge is the percentage of each bet that the casino expects to keep over the long term. So if a casino game has a house of 4%, the casino expects to keep $4 out of every $100 that you wager. It's a statistical probability that comes into play over an enormous number of wagers.

An important thing to keep in mind about the house edge is that if you're making wagers at a disadvantage, you'll lose all your money eventually if you keep playing. The higher the house edge, the sooner it will happen, but it will still happen. The only way to guarantee consistent winnings over the long term is to play a game where you have the edge instead of the casino.

Counting cards can give you that edge, but it won't give you an edge unless you're making the right playing decisions on each hand.

Some people learn basic strategy by memorizing a chart, but I learned by memorizing how to play each specific hand. You have a limited number of potential hand totals, and the dealer has a limited number of upcards, so basic strategy can be presented as a list of rules for how to play each hand in each situation.

I've provided that list below, but it assumes that you already know how to play the game. It also assumes that you're familiar with the game's terminology. If you don't know the difference between a soft hand and a hard hand, then you'll have some more studying to do before this site will become useful to you.

Also, the correct tactic for some hands changes based on the rules variation can vary, but the rules below will only be in error part of the time. If you want to generate a more specific chart for a specific set of rules, use the generator on Ken Smith's site,

Hard Hands

The tactics for hard hands are easy to learn, and that's where you should start. Remember that these are the correct way to play HARD hands, not soft hands. (Those hands are covered in the next section after this one.)

Soft Hands

Learning to play the soft hands correctly is actually easier, because there are fewer potential situations. The tactics for each possible situation follow:

If the casino's rules don't allow you to double down in certain situation, take a hit instead.

Splitting Hands

Any time you get two cards of the same rank, you have the option of splitting. If you don't split, then treat the hand as the appropriate soft or hard hand.

By following the approach above, you'll reduce the house edge so that blackjack is ALMOST an even odds proposition. The rest of this page discusses how to get an advantage.

Advantage Play and How Counting Works

Since basic strategy reduces the house edge to almost 0%, anything you can do to improve your odds starts to tilt the odds in your favor. A card counter tracks the ratio of high cards to low cards in the deck. This enables her to improve her chances in two ways.

The first way is by adjusting her decisions based on this new ratio. For example, if a deck of cards has a lot of low cards in it, then it might be appropriate to just hit a total of 11 instead of doubling down.

The second ways is by allowing the counter to increase her bets when the composition of the deck means she has an advantage. In a single deck game, the player has an advantage over the casino about half the time. That's because having certain cards in the deck increases the player's odds, while having certain other cards in the deck increases the casino's odds.

The best way to illustrate this is with an advantage. If you were playing a blackjack game that paid 3 to 2 for a natural 21, and the deck had no cards in it but 10s and aces, you'd have a clear mathematical advantage, because it would be easier to get the increased payout.

On the other hand, if you were playing in a blackjack game where there were no aces at all, it would be impossible to be dealt a natural, which would sway the math more in the casino's favor.

In the first of those two hypothetical situations, you would want to wager more money. In the second situation, you wouldn't want to wager at all--at the very least, you'd want to wager less.

Card counters increase the size of their bets when the deck favors them, and they reduce the size of their best when the deck favors the casino. If they're proficient enough, they gain a long-term edge over the house.

Learning How

Multiple systems are used by advantage players to track the ratio of high cards to low cards in a blackjack deck, but they all use a similar methodology. Rather than memorizing the specific cards which have been played, they assign a numerical value to the high cards and the low cards. This running total provides an approximation of how favorable the deck is to the player or to the casino, and the counter adjusts her bet size accordingly.

The most commonly used system is called the Hi Lo system. The Hi Lo system assigns the following values to the cards:

This is a balanced system, so if you count through an entire 52 card deck, you're running total should be 0 when you finish. And in fact, this is exactly what you should do in order to learn how to count--practice with a single deck of cards at your kitchen table until you're able to quickly deal through all the cards and get a running total of 0 at the end.

Once you're able to do that proficiently one card at a time, start dealing yourself the cards two at a time. You'll notice that many combinations cancel each other out. For example, if you deal a 10 and a 2 to yourself, the net count for those two cards is 0.

In order to pull this off when you play blackjack for real money, you need to be able to do this without looking like you're doing it. You can't move your lips. You can't look like you're concentrating. It has to be so natural to you that the casino doesn't notice.

Most people will think they have the knack of it sooner than they really do. That's because counting cards in a casino is harder than doing so in the comfort and quiet of your own home. For one thing, casinos are loud and busy, which is distracting. For another thing, you're being watched in a casino, and that will just plain rattle some folks.

The Running Count versus the True Count

To make it harder for players to get an advantage, casinos use multiple decks--sometimes as many as eight decks at a time. This reduces the net effect that each card has on the ratio of what's left in the deck.

For example, if an ace is dealt from a 52 card deck, you have 3 aces left out of 50 cards. That's 6% of the deck. But if an ace is dealt from a 416 card deck, you have 31 aces left out of 414 cards. That's 7.5% of the deck, which is a significant difference.

To compensate for the additional cards, you have to convert your running count into a true count. You do this by dividing the running count by your estimate of how many decks are left in the shoe. You make your betting and playing decisions based on the true count, not the running count.

Bankroll Management and Bet Sizing

A flat bettor bets the same amount on each hand, no matter what. Casinos are comfortable with flat bettors. Counters, though, bet the minimum when the house has the edge, then they raise their bets based on the count.

If you want to count cards, you should have a blackjack of at least 100 times the minimum bet. That means if you're playing the $5 tables, you need a bankroll of at least $500. Having a large bankroll reduces your chances of going broke because of a losing streak. Advantage gambling is about accumulating a small advantage over a lot of bets, because in the short term, anything can happen, no matter what the odds are. The actual results grow closer to the mathematical expectation the longer you play.

When the count is negative or 0, you flat bet the minimum bet. When the true count goes up, you raise your bets accordingly. Most players range their bets between one and four units, but an aggressive player might range her bets between one and eight units. The size of each bet corresponds to the true count. So if you have a true count of +4, you'd increase you bet on the next hand to four or five units to capitalize on the advantage.

Using this technique can change the house edge on a blackjack game from 0.5% to 1.5% in favor of the house to from 0.5% to 1.5% in favor of the player, depending on the conditions of the game being played.

Is It Legal?

In the United States, things are legal unless a specific law forbids them. As far as I know, no law prohibits thinking during the playing of a game. I'm not an attorney, but I'd be willing to go out on a limb and say that counting cards is legal.

Is It Cheating?

The casinos think it is. Advantage gamblers don't think so. It depends on your definition of cheating.

Since you're not modifying the conditions of the game, you're not cheating under the legal definition. Casinos, on the other hand, think that counting violates the spirit of the game, so they consider it cheating. In most jurisdictions, including Las Vegas, they have the right to ban players from their blackjack games. Atlantic City is one notable exception, but if you play blackjack there, don't expect to find conditions that are favorable to getting an edge. Since the courts ruled that they couldn't bar players, they changed the rules so that it's practically impossible to get an edge.

Can You Count Online?

Since blackjack online simulates the same 52 card deck used in a brick and mortar casino, can you use this technique to get an advantage on the Internet? Theoretically, you could, except for one wrinkle. Internet casinos use a random number generator that shuffles the deck after every hand. So the composition of the deck is entirely random at the start of any new hand. Real money online blackjack is a lot of fun, but it's not a beatable game.