Card Counting in Blackjack Explained: What It Is, How to Do It, and Is It Illegal?

Eddie Griffin

Written by: Eddie Griffin

Published:

Read Time: 13 minutes

Card counting is a strategy popularly used in blackjack to gain an advantage over the casino by tracking the ratio of high cards to low cards remaining in the deck.

While popularized by movies like “21” and “Rain Man,” the reality of card counting is more nuanced and challenging than typically portrayed.

This guide will explore the mechanics, legality, and practical considerations of card counting, both at land-based casinos and real money online casinos.

It is designed to provide an in-depth look at what it takes to master this complex skill and lay out the considerations that may help you determine if it is worth the risks that are involved.

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What Is Card Counting?

Card counting is based on a simple premise: when there are proportionally more high cards (10s, face cards, and aces) remaining in the deck, the player has a statistical advantage. Conversely, when there are more low cards remaining, the house has the advantage.

By tracking this ratio, skilled players can adjust their betting amounts based on their advantage and make more informed playing decisions. Not only can this reduce the blackjack house edge, but it can also potentially help players achieve a mathematical edge over the casino.

The advantage comes from several factors.

First, players receive a 3:2 payout on a natural blackjack, making high cards more valuable.

Second, players can choose to stand while the dealer must hit on certain totals, which gives players more flexibility when the deck is rich in high cards.

Third, players can double down or split pairs when advantageous, which becomes more profitable with certain deck compositions.

Basic Card Counting Systems

There are multiple card counting systems that players can use when playing blackjack. The most well-known system is the Hi-Lo system.

Hi-Lo System

The most common and straightforward counting system is the Hi-Lo method.

In this system, low cards (2-6) are counted as +1, medium cards (7-9) are counted as 0, and high cards (10-Ace) are counted as -1.

Players maintain a “running count” by adding these values as cards are dealt. This count must then be converted to a “true count” by dividing by the number of decks remaining (if you are not playing a variant of single deck blackjack), allowing for accurate betting decisions.

The Hi-Lo system is popular because it strikes an excellent balance between accuracy and ease of use.

It has a betting correlation of 0.97 and a playing efficiency of 0.51, making it highly effective despite its relative simplicity.

Other Card Counting Systems

Over the years, several more sophisticated card counting systems have been developed.

The Hi-Opt I system ignores aces in the count. That makes it easier to maintain, but it requires a separate ace side count.

The Hi-Opt II system assigns different values to different cards, providing greater accuracy at the cost of complexity.

The Omega II system, developed by Bryce Carlson, uses multiple count values and provides excellent accuracy. However, it is considerably more challenging to master than other card counting systems.

The Wong Halves system, created by Stanford Wong, uses fractional values for certain cards. That makes it one of the most accurate systems available, but it is also one of the most difficult to use in practice.

The Zen Count attempts to balance complexity and accuracy by using a wider range of numbers while maintaining reasonable usability.

How to Count Cards: A Step-by-Step Guide

So, now that you know the basics of card counting and card counting systems, what are the steps involved in card counting?

Note that this is not an endorsement to count cards. Do so at your own risk. Be aware of the potential peril of doing so.

Step 1: Learning Basic Strategy

Before attempting to count cards, one must thoroughly master basic blackjack strategy.

This foundation ensures you’re making optimal decisions for each hand combination regardless of the count. Basic strategy involves memorizing the correct play for every possible player hand against every possible dealer upcard.

This includes knowing when to hit, stand, double down, split pairs, and surrender if available. The strategy must become second nature before adding the complexity of counting cards.

There are numerous blackjack variants and games, including American blackjack, European blackjack, and multi-hand blackjack. Also, blackjack side bets are often a consideration. But the basics principles and objectives of blackjack are the same across the board. Make sure you have those basics down before diving into card counting.

Step 2: Maintaining the Running Count

Maintaining an accurate count when card counting requires significant practice and concentration.

Begin by practicing with a single deck, dealing cards face up at a steady pace. Start the count at zero and adjust it as each card appears. Work on recognizing patterns and combinations of cards to speed up your counting.

For example, if you see a 5 and a 2 together, you should immediately recognize this as +2 to your count.

Practice counting through the entire deck until you can accurately reach the final count (which should be zero in a complete deck) within 20-30 seconds.

Once you’ve mastered single-deck counting, move on to multiple decks and increase your speed gradually. Practice counting with distractions to simulate casino conditions.

Step 3: Converting to True Count

In card counting, having an accurate true count is crucial. Doing so helps players make the right betting decisions in multiple-deck games.

To convert your running count to a true count, you must estimate the number of decks remaining in the shoe and divide your running count by this number.

For example, if your running count is +8 and there are approximately 2 decks remaining, your true count would be +4.

Deck estimation requires practice and attention to detail. Most card counters use the discard tray as a reference point, developing the ability to quickly estimate remaining deck depth.

Some counters also use physical markers or betting patterns to track approximate deck penetration.

Step 4: Betting Correlation

Your betting strategy in blackjack games should correlate directly with the true count.

Most successful card counters use a progressive betting strategy that increases bets as the count becomes more favorable.

A typical betting spread might start with one unit at negative or neutral counts and increase to two units at a true count of +1, four units at +2, and so on up to the table maximum or your predetermined maximum bet.

The size of your betting spread should balance several factors:

  • 1) the need to capitalize on favorable counts,
  • 2) the desire to avoid detection, and
  • 3) your bankroll requirements.

While larger spreads provide better theoretical returns, they also attract more attention from casino personnel.

Card Counting: Legality and Casino Responses

Is Card Counting Legal or Illegal?

Card counting is technically legal in most jurisdictions. However:

  • Casinos are private properties and can refuse service to anyone
  • Using electronic devices or external aids for counting is illegal
  • Some jurisdictions have specific laws against advantage play

Casino Countermeasures

Casinos employ various methods to prevent card counting:

  • Frequent shuffling
  • Multiple deck shoes
  • Shuffle tracking
  • Facial recognition software
  • Training dealers to spot counting behaviors

Backoffs and Consequences of Card Counting

If caught counting cards, you may face:

  • Being asked to leave (“backoff”)
  • Being banned from the casino
  • Having your photo shared with other casinos
  • Potential trespassing charges if you return after being banned

Practical Considerations for Card Counting

Requirements for Card Counting Success

To be a successful card counter, you need:

  • Significant bankroll (typically 100-200 times your maximum bet)
  • Excellent mathematical skills
  • Strong memory and concentration
  • Ability to maintain composure under pressure
  • Time to practice and perfect the technique
  • Willingness to accept financial risk

Challenges and Limitations of Card Counting

Modern casino practices make card counting increasingly difficult:

  • Continuous shuffling machines
  • Poor game conditions (6:5 blackjack payouts)
  • Increased scrutiny of players
  • Need for travel between casinos
  • Emotional and psychological stress

Expected Return of Card Counting

Even with perfect play:

  • Edge over the house is typically 0.5% to 1.5%
  • Results can be highly volatile
  • Significant time investment required
  • Risk of losing entire bankroll exists

Additional Considerations for Card Counting Success

Bankroll Management

Proper bankroll management is crucial for long-term success in card counting. Your total bankroll should be large enough to withstand the natural variance in the game while allowing you to maintain appropriate bet sizing.

As noted above, most experts recommend a minimum bankroll of 200 times your maximum bet for a single session, with a total bankroll of at least 1000 times your maximum bet to account for potential downswings.

Team Play Considerations

Many successful card counting operations have utilized team play to increase their effectiveness and reduce individual risk. Team play can take various forms, from simple partnerships where players share information about hot tables to sophisticated operations with multiple roles including spotters, big players, and shadow players.

While team play can be more profitable than solo counting, it introduces additional complexities in terms of trust, coordination, and profit sharing.

Why You Should or Should Not Count Cards

Potential Benefits to Card Counting

  • Intellectual challenge and skill development
  • Possibility of long-term profit
  • Understanding of probability and statistics
  • Strategic thinking development

Significant Drawbacks to Card Counting

  • High stress and anxiety
  • Risk of substantial financial losses
  • Potential casino confrontations
  • Time-consuming practice requirements
  • Need for perfect concentration
  • Social stigma and secrecy

Card Counting in Online Blackjack

The information found here focuses on blackjack games in brick-and-mortar casinos.

But can card counting be done at blackjack sites such as Lucky Red Casino and OnlineCasinoGames? Also, is it possible to count cards in live dealer blackjack?

Traditional Online Blackjack

Card counting in traditional Random Number Generator (RNG) online blackjack is effectively impossible.

Why is that the case?

RNG games, which are created by online casino game providers such as RealTime Gaming (RTG) and Betsoft and available at online casinos such as Slots Ninja and Uptown Aces, use continuous shuffling algorithms that randomly generate each card for every hand.

Since there is no persistent deck or shoe being depleted, players have no way to attain an advantage through card counting. Each hand is completely independent of the previous hands, which makes tracking card ratios meaningless.

Live Dealer Blackjack

Live dealer blackjack, which is found at sites such as Wild Casino, DuckyLuck Casino, and HighRoller Casino presents a more interesting scenario for card counters.

These live dealer games use real cards dealt by human dealers. Theoretically, that makes card counting possible.

However, several factors make it significantly more challenging and less profitable than traditional casino card counting.

What are some of these factors?

  • Deck Penetration: Most live dealer games use automatic shuffling machines or very frequent manual shuffles. The deck penetration (how far into the shoe the dealer deals before shuffling) is typically much lower than in physical casinos. That severely limits card counting opportunities in live dealer blackjack.
  • Cut Card Placement: Online casinos often place the cut card earlier in the shoe than physical casinos. This reduces the number of hands played before shuffling and limits the potential advantage from counting.
  • Betting Limits and Restrictions: Live dealer games frequently impose strict betting limits. Also, they may restrict mid-shoe entry or bet size variations. These restrictions directly target counting strategies that rely on varying bet sizes based on the count.

Online Casino Countermeasures

Online casinos employ various technological and procedural measures to prevent or limit card counting:

  • Software Analytics: Online casinos use sophisticated software to track betting patterns and player behavior. These systems can identify suspicious patterns such as consistent bet variation that correlates with favorable counts.
  • Session Monitoring: Unlike physical casinos where players can move between tables anonymously, online casinos such as SlotsandCasino and Super Slots Casino can track every aspect of a player’s behavior across multiple sessions. This makes it easier to identify and flag potential advantage players.
  • Automatic Restrictions: When suspicious patterns are detected, online casinos can automatically implement restrictions such as reduced betting limits, forced minimum bets, or account reviews.
  • Multi-Account Detection: Online casinos use advanced systems to detect related accounts, making it difficult for counters to spread their action across multiple accounts or operate as teams.

Technical Limitations for Online Card Counting

Several technical factors make online card counting particularly challenging. This includes:

  • Video Delay: Live dealer games often have slight streaming delays. That can make accurate counting more difficult and reduce the time available for decisions.
  • Camera Angles: Limited camera views may make it harder to spot all cards being dealt. This is particularly the case in multi-player games.
  • Connection Issues: Internet connectivity problems can cause missed hands or incomplete information. That can disrupt the count and reduce accuracy.

Alternative Online Strategies

Given the significant challenges of counting cards online, players interested in advantage play might consider these alternatives:

  • Game Selection: Focus on finding online blackjack games with favorable rules and payout structures rather than attempting to count cards.
  • Bonus Optimization: Learn to identify and maximize value from online casino bonuses and promotions. The best online casino promos often provide better expected value than attempting to count cards.
  • Skill Development: Use online play to perfect basic strategy and practice counting techniques in a low-pressure environment before attempting to count in physical casinos.

Alternative Approaches to Advantage Play

Instead of card counting, consider:

  • Learning perfect basic strategy
  • Taking advantage of casino promotions
  • Participating in VIP and loyalty rewards programs
  • Playing other games with better odds
  • Focusing on poker or sports betting where skill is explicitly allowed

Conclusion

Card counting represents a fascinating intersection of mathematics, psychology, and gambling.

While technically legal, it requires exceptional dedication, skill, and risk tolerance. Most people who attempt card counting fail to achieve profitability due to the numerous practical challenges and casino countermeasures.

For most players, focusing on basic strategy and responsible gambling practices will provide a more enjoyable and sustainable casino experience. But if you’re mathematically inclined and seeking a challenge, card counting can be an interesting intellectual exercise – but approach it with realistic expectations about the difficulties and risks involved.

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Card Counting FAQ

Is card counting illegal?
Card counting itself is not illegal in most jurisdictions. However, casinos are private properties and can ban players they suspect of counting cards, while using electronic devices or external aids for counting is illegal.
Spoiler title
Can I make a living counting cards?
Even with perfect play, the edge over the house is typically only 0.5% to 1.5%, requiring a substantial bankroll and significant time investment. Most people who attempt card counting fail to achieve sustainable profitability.
Can I count cards in online blackjack?
Traditional online blackjack uses random number generators with continuous shuffling, making card counting impossible. While technically possible in live dealer games, frequent shuffling and strict betting limits make it impractical.
How long does it take to learn card counting?
Learning a basic counting system like Hi-Lo can take a few weeks of dedicated practice. However, becoming proficient enough to count in a casino environment while maintaining composure typically takes several months.
What is the minimum bankroll needed for card counting?
Experts recommend a minimum bankroll of 200 times your maximum bet for a single session, and at least 1000 times your maximum bet for your total bankroll. For a $25 maximum bet, you’d need at least $25,000 total.