Casino countermeasures and legality

Key facts

Counting cards in your head is not a crime under British law or under US federal, state or local law, provided no device or outside help is used.
In most jurisdictions, including Nevada, a casino may refuse to let a player play blackjack or exclude them from the property.
In New Jersey, following Uston v. Resorts International Hotel (1982), Atlantic City casinos may not bar players for card counting.
Nevada Revised Statutes 465.075 makes it unlawful to use or possess a device that keeps track of cards played or analyses probabilities or strategy at a licensed game.
Continuous shuffling machines, early shuffles, flat-bet requirements and no mid-shoe entry are the usual countermeasures and each removes or limits a counter's information or spread.

Card counting is legal: thinking about the cards you have seen breaks no law in Britain or the United States. What the law does not do is oblige a casino to deal to you. In most jurisdictions a casino may stop a suspected counter from playing blackjack or exclude them altogether, and short of that it has a toolkit of game changes that make counting unprofitable. This page separates the legal position from the practical one and lists what counters actually run into.

The legal position

Wikipedia’s card counting article states the general rule: card counting is not illegal under British law, nor under federal, state or local laws in the United States, provided no external device or person assists the player in counting. The player is using information the casino shows them and is following the rules of the game. The advantage gambling article makes the same point for advantage play generally: it is not fraud, because the player follows the game’s rules, but it may result in players being banned by certain casinos.

Three things turn a legal activity into an illegal one almost everywhere:

Devices. Any electronic or mechanical aid for tracking cards or computing strategy (see below).
Collusion with casino staff. A dealer who flashes a card or a floor supervisor who looks away is committing an offence, and so is the player who arranged it.
Marking, switching or tampering with cards or chips. These are cheating in every jurisdiction regardless of what a counter does with the information.

Team play, in which one player signals another, sits outside these: nobody is being deceived about the cards and no device is involved. It is nonetheless the pattern casinos are most alert to.

Nevada versus New Jersey: who decides who plays

The two big US markets reached opposite answers on whether a casino may exclude a counter.

Nevada. Wikipedia’s card counting article describes Nevada as a jurisdiction with few legal restrictions on casino countermeasures, and cites a Nevada court ruling that card counting itself is not illegal under Nevada law. The practical effect is that Nevada casinos may bar a player for counting at their discretion; the player has committed no offence and the casino has exercised its right to choose its customers.

New Jersey. Ken Uston, the best-known counter of the 1970s, was barred by Resorts International in Atlantic City in January 1979 and sued. The Wikipedia article on Uston records the outcome: in Uston v. Resorts International Hotel, Inc. (445 A.2d 370, N.J. 1982) the New Jersey Supreme Court held that Atlantic City casinos did not have authority to decide for themselves whether card counters could be barred; exclusion was a matter for the state Casino Control Commission, which had made no regulation excluding counters. New Jersey casinos therefore cannot bar card counters. Wikipedia’s advantage gambling article lists Missouri alongside New Jersey as a state where a player may not be asked to leave for counting.

What New Jersey casinos did instead is instructive. The Uston article records that Atlantic City responded by adding decks, moving up the shuffle point and taking other measures to reduce a skilled player’s advantage. A casino that cannot bar you can still shuffle early, cap your bet or require flat betting, and the advantage gambling article notes that such restrictions remain available even where exclusion is not. A counter is often better off where casinos bar individuals and leave the game alone than where the game is degraded for everyone.

Device laws

Nevada Revised Statutes 465.075 makes it unlawful to use, possess with intent to use, or assist another person in using or possessing any computerised, electronic, electrical or mechanical device, or any software or hardware, designed or programmed to obtain an advantage at a game in a licensed gaming establishment, including without limitation a device that:

projects the outcome of the game;
keeps track of cards played or cards prepared for play;
analyses the probability of the occurrence of an event relating to the game; or
analyses the strategy for playing or betting to be used in the game,

except as part of an approved game or as otherwise permitted by the Commission. A phone app that tracks the count falls squarely within the second and fourth limbs. Possession with intent is enough; the device does not need to have been used. Wikipedia’s card counting article notes that Macau takes the same view of electronic aids, where their use can lead to arrest.

This is the bright line between advantage play and crime. A counter keeps everything in their head, and the moment any apparatus is involved the activity changes category.

Countermeasures casinos use

Wikipedia’s card counting article lists the standard responses. Each works by removing information, removing the spread or removing the player.

Countermeasure	What it does to the counter
Reduced penetration (earlier cut card)	Fewer cards seen before the shuffle, so the count rarely reaches useful values; the single most effective quiet measure
Preferential shuffling	The dealer shuffles when a player raises a bet or when the remaining cards favour the player, destroying the count exactly when it has value
Continuous shuffling machine (CSM)	Discards go back into the machine after every round; composition never drifts and there is nothing to count
Flat-bet requirement or no bet changes mid-shoe	Removes the spread, which is where the edge comes from
No mid-shoe entry	Prevents back-counting (standing behind the table and sitting down only when the count is high)
Rule changes	Tightening doubling, splitting or multiple-hand rules, or changing table limits, to cut the counter’s gain per high-count hand
Backing off or barring	Being told you may play other games but not blackjack, or asked to leave; adding the player to a shared database
Cancelling comps	Removes the hidden subsidy that makes marginal play worthwhile

The article also records confiscating chips and detaining players as responses that have occurred; both are legally contentious, and a counter who is detained should ask for the gaming regulator.

Shuffle machines deserve a note. A CSM is different from an automatic batch shuffler. A batch shuffler mixes one shoe while another is dealt, and the dealt shoe is countable as normal. A CSM, as the shuffling machine article describes, shuffles one or more packs continuously, with discards fed back in during play; it is the version that defeats counting. How a shoe game is dealt explains how to tell them apart at the table.

Being backed off

The usual sequence is: a floor supervisor watches, surveillance reviews the bet pattern against the count, and a supervisor or security officer approaches with a scripted line such as “you’re welcome to play any other game”. Sometimes it is a request to leave the property, with a trespass warning that makes a return a criminal matter in that jurisdiction. Chips are normally cashed out as usual.

What triggers it is the signature of counting rather than winning. Wikipedia’s article lists the tells surveillance looks for: a bet spread that rises and falls with the count, large bets placed only late in the shoe, and unusual plays such as splitting tens, doubling soft 18 to 20, standing on 15 and 16, surrendering 14 and taking insurance on small hands. Casinos share information through surveillance databases, and the article notes that face recognition and image databases are part of the detection toolkit; the MIT team was eventually linked by investigators through the Cambridge addresses of banned players.

Arguing, refusing to leave, or returning after a trespass warning converts a civil inconvenience into a police matter; the counter who nods, cashes out and leaves keeps the option of playing elsewhere.

What this means for a player

The honest summary: counting is legal; being allowed to count is not a right outside New Jersey and Missouri; and the casino does not need to catch you to beat you, because shallow penetration, a CSM or a flat-bet rule makes the question moot. Game selection is therefore as much a part of counting as the count itself. A six-deck game with five decks dealt and a tolerant floor is worth more than any system; a game with a CSM is worth nothing to a counter whatever their skill.

Everything on this page concerns real-money casino play. Blackjack World Tour is a free iOS blackjack game played with virtual chips; it is a social casino with in-app purchases and no real-money gambling.

Frequently asked

Is card counting illegal?

No. Counting cards mentally is legal in the UK and throughout the United States. What is illegal in many places is using a device, software or an accomplice to do the counting or analysis for you.

Can a casino throw me out for counting?

In most jurisdictions, yes: casinos are private businesses and may refuse service or ask a player to leave. New Jersey is the main exception, where regulators rather than casinos control who may be excluded.

What happens when you get backed off?

A floor supervisor or security tells you that you may play any game except blackjack, or may not play at all, and sometimes that you are no longer welcome on the property. Chips are normally cashed out; detention or confiscation would be a matter for the local regulator.

Can you count cards against a continuous shuffling machine?

Not usefully. Discards are returned to the machine and remixed continuously, so the composition of the next cards never drifts far from a full shoe and there is nothing for the count to track.

Is a card counting app on my phone legal at the table?

In Nevada, using or possessing a device that tracks cards or analyses strategy at a licensed game is a criminal offence under NRS 465.075. Other jurisdictions have similar rules. Leave it in your pocket, switched off.

Sources & editorial notes

By Blackjack World Tour · Updated 2026-10-12 · Owner review pending. Sources were checked on the update date.

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