21 Things You Didn't Know about Blackjack

21 things you didn't know about Blackjack With Card Table Custom Image

Gambling is more popular than ever, and blackjack is easily the 2nd most popular game in most casinos. But how exactly does the casino make money from a blackjack game? Can a gambler really get an edge over the house if he's skilled enough? What are the differences between the variations? I put together this list of 25 sometimes surprising and always interesting bits of trivia about the game of blackjack.

1. The Slots Club Card Works At the Blackjack Table

A lot of players don't realize that they can use their slots club card at the blackjack table. In fact, your players' club card (another name for slots club card) can be used at any table game in the casino. The dealers estimate how much you're betting on average per hand and multiply that by how many hands per hour on average you're playing in order to determine how many rewards points you've earned.

If you want detailed instructions for combining skilled blackjack play with casino comps in order to get an edge over the casino, read Max Rubin's book, Comp City. He details how to convince the casino that you're betting more on average than you actually are. He also explains how the casino calculates your expected loss per hour versus how you can minimize that expected loss by using perfect basic strategy.

2. Blackjack is More Than Just One Game.

Sure, the basics of blackjack are the same from game to game and from table to table. Your goal is always to get as close as you can to a total of 21 without going over. The cards have the same values from game to game-their face value, or 1 or 11 if you're looking at an ace, or 10 if you're looking at a face card. But the little rules variations can add up to make some versions of blackjack entirely different games.

Spanish 21 is one example. It's even played with a slightly different deck. They remove the 10s (but not the jacks, queens, or kings) from a standard deck to create what's called a "Spanish" deck. (Spanish 21 isn't the only game that uses a Spanish deck, either.)

A blackjack always pays 3 to 2 in Spanish 21, though-even when the dealer has a blackjack, too. Players who play traditional blackjack understand what a major difference that is. A push happens more often in blackjack than most people think.

Other blackjack variations offer side bets and progressive jackpots. You can even play video blackjack, which is more similar to table based blackjack than video poker is to traditional poker.

3. The House Edge In Blackjack, if You Play With The Correct Strategy, is Usually Less Than 1%.

The house edge of a casino game is the amount of each bet that the casino expects to keep in the long run-over a nearly infinite number of hands. Most casino games have a house edge of around 5%, although it varies dramatically. But the only game in the casino that even comes close to the low house edge of blackjack is video poker.

If you're betting $100 per hand, the casino expects to win (on average) $1 per hand in a game with a 1% house edge. The rules variations in place at the casino and at the table where you're playing affect the house edge.

4. The Most Important Factor That Determines The House Edge In Blackjack is The Payoff for A Natural.

A "natural" is the same thing as a "blackjack"-a 2 card hand with a total of 21. There's only one way to get this hand-be dealt an ace along with a card worth 10. The standard rule for years has been that a player with a natural gets paid off at 3 to 2.

A common technique that casinos now use to improve their edge over the player is to reduce the payoff for this hand-instead of offering 3 to 2, they might offer 6 to 5. If you can find a casino that offers 2 to 1, you're dealing with a very generous casino. Video blackjack games sometimes only offer even money payouts for naturals, which increases the house edge dramatically.

If you can find a game with an increased payout of 2 to 1 for this hand, the house edge is reduced by a whopping 2.27%. That's $2.27 per hand if you're betting $100 per hand.

But if you play in a game with a 6 to 5 payoff for this hand, the house edge increases by 1.39%. That might not sound like much, but it's a huge difference when you're talking about a game which might have started off with a house edge of around 0.5%.

My recommendation is to just say no to 6/5 blackjack games altogether.

5. Your Average Hourly Loss is Easily Calculated by the Casino.

The casino determines your rebates and rewards as a player club member by calculating your average expected loss per hour. And they get a remarkably accurate estimate of what that number will be in general. The formula is simple:

Average number of bets per hour X Average bet size X House edge

The average number of bet per hour varies based on how many players are at the table, as follows:

Of course, the average bet size is up to the player, but let's assume that you're flat betting $100 and you're the only player at the table. This means you're putting $20,000 per hour into action. Of course, it's extremely unlikely you'd lose all of those 200 hands-but when you add up the wins and losses and get your net loss, over a significant period of time, it will come close to the house edge.

But the casino assumes that you're an average player. The average blackjack player makes a strategy mistake about 15% of the time. These mistakes add about 2% to the casino's edge. In fact, in Las Vegas, it's even worse-2.25%.

The casino will assume that you're going to lose about 2% of the $20,000 you put into action in that example, or $400. In the short run, of course, you might be winning more than that or losing more or less than that. But if you play long enough, your results will probably come pretty close to that number.

On the other hand, if you memorize and use basic strategy, you can reduce the house edge to between 0.5% and 1%, depending on the rules variations in place. That means losing between $100 and $200 per hour instead of $400 per hour.

Keep in mind, too, that the casinos are calculating your rewards based on the 2%, not the 0.5%, so you're going to bet getting freebies and rebates. This will make your average expected loss per hour even less.

6. Mathematicians Know The Effect of Every Imaginable Rule Change On The Odds.

There are a surprising number of ways a casino can differentiate one blackjack game from another. Each of these rules variations either adds or subtracts to the house's edge over the player. Knowing the effect of each rules change can help you decide which blackjack game is better than the others.

One example is the payoff for a natural-we already discussed that.

Another example is the number of decks in play. The more decks the casino uses, the higher the house edge:

A single deck game subtracts about 0.5% from the house edge. This is the best possible scenario.

A double deck game subtracts about 0.2% from the house edge. It's still a good deal, and both single and double deck games are rare.

A game with 4 decks doesn't really affect the edge much-less than 1/10 of a percent, in fact.

Of course, all of these numbers are relative to the standard in casinos these days-the 8 deck game.

Another example is whether or not the dealer hits a soft 17. If the dealer stands on all 17s, including the soft ones, that's the standard rule. But if the dealer hits a soft 17 instead, the house gains about 0.2%.

7. Card Counting Really is A Thing.

If you've only been exposed to card counting via television and the movies, you might be a little confused about whether or not it really works, and if so, how it works. I know people who have seen Rain Man who are convinced you have to be an idiot savant capable of memorizing an entire deck of cards.

But that's not how it works at all.

Blackjack differs from other casino games because it has a memory. Once a card has been played from a deck, the deck changes, and so do the odds of getting various hands.

If that doesn't make sense, think about this:

Suppose we're playing blackjack and all the aces have already been dealt.

What are your odds of getting a dealt a blackjack?

If you said 0, give yourself a pat on the back. You can't get a blackjack without the aces in the deck.

In fact, having lots of aces and 10s still in the deck increases the chances of being dealt a blackjack, while having lots of lower value cards in the deck decreases the chances of being dealt a blackjack. If you had some way of knowing how many aces and 10s were still in the deck, you could raise your bets when you had a better chance of getting a blackjack and lower them when you had a worse chance of getting a blackjack.

And since that hands pays off at 3 to 2, that would have a big effect on your overall expected win or loss.

This is, in fact, the basic premise behind counting cards. Here's an example of how such a system works:

You subtract 1 from the count every time an ace or a 10 is dealt.

You add 1 to the count every time a 2, 3, 4, 5, or 6 is dealt.

When the count is positive, you have an edge over the casino, and you should raise your bet. The higher the count, the better your odds are, and the more you should bet.

When the count is 0 or negative, you don't have an edge over the casino. So you should bet the minimum.

But that's not the only way card counters get an edge over the casino. They can also make strategy adjustments based on the count. The most significant of these is whether or not to take insurance. If the deck is rich in 10s and aces, and the count is positive, then taking insurance makes sense mathematically.

8. Casinos Really Do Hate Card counters.

If you've seen the movie 21, you probably have a pretty good idea already of the casinos' attitudes toward card counters. They're not in the business of giving the players an edge over the house. As a result, they're surprisingly willing to turn away customers who demonstrate too much skill at the tables.

But it's important to point something out:

Card counting isn't illegal anywhere.

If you think about it for a second, you'll realize how ludicrous it would be to make such an activity illegal. After all, we're talking about thinking about the game you're playing while you're playing it. Most people who think they can count cards are lousy at it, anyway. I think a lot of casinos jump on suspected card counters with too much enthusiasm. They'd be better off letting these wannabe pros continue to lose money at the tables.

9. You Can't Count Cards in Online Blackjack Games.

The reason for this is simple-online casinos always shuffle the deck after every hand. This applies to standard online casino versions of blackjack, which are powered by a computer program called a random number generator (RNG).

But it also applies to live dealer casinos.

I've seen posts on poorly written gambling blogs which claim that one of the advantages of playing at a live dealer casino is being able to count cards. Sorry-that's not the way it works. Even live dealer casinos shuffle after every hand.

10. The Random Number Generators In Online Casinos Duplicate The Probabilities Found in A Standard Deck of Cards.

Some players worry that they're playing a game that only LOOKS like blackjack when they're playing online. But the truth is that it's easy for a computer program to duplicate the action found in a standard deck of cards.

Here's how it works, in short:

The random number constantly generates numbers between 1 and 52. Each of those numbers corresponds to a playing card. The program puts those numbers into a random row, then it "deals" the cards, just like you would if you had just shuffled a deck.

Some players worry that online blackjack games are rigged. They think that maybe their odds of winning go down if they're on a winning streak. Or maybe they think the random number generator has been programmed to deal fewer blackjacks than you would normally expect.

But here's the thing:

The house already has an edge over the player. They don't NEED to rig the game in order to win in the long run. They've already set the game up so that they have an unassailable mathematical advantage over the player.

Yes, there are crooked casinos out there. But they're more likely to delay your payouts when you're winning than they are to rig their games. Some of them never pay their winners. If a rogue casino doesn't pay out the players who win, they have no need to rig the games.

11. Blackjack Isn't The Game for Casino Bonus Hunters.

Online casinos attract new real money players by offering deposit bonuses. Here's how these kinds of promotions work:

When you make your first deposit at the casino, you get a bonus equal to a certain percentage of your deposit. These usually have a maximum limit.

Here's an example:

Casino A offers a 100% matching bonus on your first deposit of $1000. You deposit $1000, and you get to play with $2000.

This sounds like a great deal, and it's not a bad deal. But it's not a deal for blackjack players.

You see, in order to prevent players from taking advantage of bonus offers and getting a mathematically guaranteed win from various casinos based on these bonuses, the casinos require players to make a certain amount of wagers in order to cash out. Usually this is 25X or more.

In the example above, you'd need to wager 25X $2000, or $50,000 before cashing out.

If you're smart, you calculate that with the best blackjack game there, with perfect basic strategy, your expected loss is only 5% of that amount, or $250.

You deposit $1000. You get another $1000 in bonus money. Then you lose $250, so you have $1750 left.

You cash out with a $750 profit.

If only it were that simple.

I don't know of any online casino which allows blackjack wagers to count toward their wagering requirements.

In fact, most online casinos require you to place the required wagers on the slot machine games. Since most slots have at least a 5% edge, you're looking at an expected loss of $2500 on those required wagers. That is, of course, more than you had in your bankroll, so the casino expects to walk away a winner.

I have seen casinos that count part of your wagers on blackjack toward these wagering requirements. Usually they only count 10% of your wagers, though, so you might as well be playing the slots. Placing $500,000 in blackjack bets would take forever, and you'd still have little chance of walking away a winner. Your expected loss would be $2500, just like with the slot machine example.

So if you're thinking about launching a career as a professional online blackjack player, well, forget it.

12. Blackjack is One of The Oldest Games in The Casino.

The first time blackjack is mentioned in literature is in Don Quixote by Miguel Cervantes. This book is considered the first true Western novel, and it was published in 1605. Cervantes was a contemporary of Shakespeare's, so that should give you a rough idea of how old this gambling game is.

Of course, Cervantes was a Spanish author, and the name "blackjack" didn't come to prominence for centuries. The game mentioned in Don Quixote was called "ventiuna". The book doesn't include a detailed description of how the game was played, but it is clear that the goal was to get a total of 21. It was also clear that the ace counted as either 1 or 11.

It's hard to imagine another card game besides blackjack that this game could be.

13. Payouts For A Blackjack Used To Be A Lot Better Than They Are Now.

When the game originally became popular in gambling halls in the United States, a blackjack paid off at 10 to 1 instead of 3 to 2. But it was a lot harder to get a blackjack, as the definition of the hand was considerably stricter. It only counted as a blackjack if it was a 2 card total of 21, but the hand also literally had to include a black jack. There are only 2 of those in the deck-the jack of clubs and the jack of spades.

Eventually the casinos realized that a smaller payout that happened more often would motivate players to gamble more, so they changed the rule to the standard 3 to 2 payout that we now commonly see.

14. Poker Players Go On Tilt, But Blackjack Players "Steam".

With the rise in popularity of televised poker, everyone in America is now familiar with the expression "tilt". But if you missed it, a poker player who's on tilt is having an emotional reaction to how the game is going. Usually they're betting a lot of chips on hands which are unlikely to win.

The corresponding term in blackjack is "steaming". A player who's steaming at the blackjack table is making bad decisions and betting more than he probably should.

If you have a cruel streak, you might enjoy watching this happen. But if you have a heart, you might feel more empathy for a player who's steaming at the blackjack table.

15. Card Counters Often Work In Teams.

Do you remember how earlier I mentioned that casinos will run you off if they think you're counting cards?

They can't run you off if they don't know you're counting cards.

But how do they know?

It's actually pretty easy to spot a counter. He's usually raising and lowering his bets based on the count.

Blackjack teams have an interesting approach to this. They'll have multiple players flat betting at multiple blackjack tables and counting. When the count gets favorable enough, they'll signal one of their confederates, who is usually playing the part of a high roller. When this teammate sees the signal, he sits down and places a huge bet.

The MIT Blackjack Team is probably the best known example of a card counting team.

16. There Are Actually More Than One MIT Blackjack Teams.

The book Bringing Down the House and the movie 21 imply that there has only ever been one MIT Blackjack Team, but the reality is that multiple card counting teams have sprung up at the university over the years. Some of this has to do with members of one team splitting off and forming their own team after having some kind of disagreement with the original team.

At any rate, take both the book and the movie with a huge grain of salt, because both have a surprising number of inaccuracies and embellishments in them.

17. Even Though Blackjack Is Hundreds of Years Old, Card Counting As We Know It Has Been Around Far Less Than A Century.

The first real mathematical coverage of card counting was in Ed Thorp's excellent book, Beat the Dealer, which was published in 1962. Since then, countless books have been published explaining different ways to get an edge over the house. But before 1962, there was no mathematical proof that the game could be beaten.

That being said, Thorp explains that multiple colorful characters had rudimentary card counting systems that might have worked with a varying degree of success.

18. Blackjack Is One Of The Only Games In The Casino Where Your Decisions Matter.

I probably should have mentioned this earlier in the post. Video poker and blackjack are the 2 main casino games where you can make decisions which improve your odds over the house. Good strategic decisions only won't get you an edge in blackjack, but it will reduce the house edge dramatically-in some cases, to less than 1%.

"Basic strategy" is the expression experts use to describe the correct decision in every single situation that can come up during a game. You have 2 things to take into account:

  1. Your total
  2. The dealer's upcard

When you know these 2 pieces of information, you can learn the correct play in every situation.

And if you think about it, there aren't that many situations to begin with. The dealer can only have one of 10 possible upcards.

Some people like to learn basic strategy visually via a colorful chart or table. I prefer to learn it using text. I learned basic strategy by studying Sklansky Talks Blackjack, which is a great book for anyone interested in taking their game to the next level.

19. Basic Strategy Changes Along With The Rules Of The Game.

Not all blackjack games are created equally. We've already talked about some of the rules variations and the effect they have on the house edge.

But you should also know that these rules variations can affect what the correct play in various situations is.

Basic strategy can change based on any of the following factors:

20. The Best Blackjack Games In Las Vegas Have A House Edge Of Less Than 0.25% If You Play With Perfect Basic Strategy.

Game rules and conditions can change at any time, but I've seen reports of blackjack games in Las Vegas which have a house edge well under 0.5%. The best of these have a house edge of around 0.25%.

The casinos which offer these games are generally on the upper end, and you'll be more likely to find favorable rules at the higher stakes games. If you're only interested in betting $5 per hand, you're going to have a hard time finding a game with a house edge this low.

Treasure Island might be your best option. The minimum bet on their best blackjack game is only $25, which is significantly lower than what you'd expect from some of the other casinos offering such great games.

Other casinos have a minimum bet of $100 at these tables. Some of them include Cosmopolitan, Mandalay Bay, MGM Grand, and Mirage.

Look for the 2 deck games where the dealer stands on soft 17. These games all allow you to double down on any total and allow you to double down after splitting.

These are the perfect games to play if you want to implement the strategies in Max Rubin's book Comp City.

21. Most Side Bets In Blackjack Are For Suckers.

Casinos offer more side bets in blackjack games every year. Almost all of these bets offer an extremely high house edge, especially when compared to the house edge on the blackjack games.

Here's an example of a side bet:

It's called "Super Sevens". It's based on your 1st 3 cards. If your first card is a 7, you win a certain amount. If the next card is a 7, you win more. And if all 3 cards are 7s, you win even more.

If the cards are suited, the payouts are even higher.

If you get all 7s of the same suit, the payoff is 5000 to 1, which sounds really impressive.

But what you have to factor in is how likely it is to win the bet compared to its payoff.

The house edge for this side bet varies based on how many decks are in play, but in the best case scenario, it's over 9%. You'd be better off playing slot machines. And under the worst conditions, the house edge on this bet is almost 17%. Heck, you'd probably do just as well playing keno.

My advice is to just flat out ignore side bets altogether. The only worthwhile side bet is insurance, and it's only a good bet if you're counting cards.


Blackjack is more than just an interesting card game-it's one with a rich, colorful history. And it's also one of the only games in the casino where you can get an edge. Even if you're not willing to put in that amount of work, you can still play this game and enjoy some of the best odds in the casino.