Blackjack › Questions › Card counting
Is card counting legal?
Yes, in the United States and in most countries, as long as you use only your head. No law bans keeping track of the cards dealt. Casinos are private businesses, though: they can ask a counter to stop playing blackjack or to leave, and in most places bar them from the property. Using a device or a phone app to count at the table is a crime in Nevada and in many other jurisdictions.
What casinos do instead of calling the police: shuffle early, cap your bet, or ask you to play anything but blackjack.
What a casino can do
A dealer or pit boss who suspects counting usually starts with countermeasures: shuffling the shoe early, moving the cut card up, limiting your bet, or forbidding mid-shoe entry. The next step is the back-off, a polite request to play any other game. The last is a trespass warning, after which coming back is a crime. None of that involves the police unless a device is found.
Why
Counting is thinking about information the casino shows every player. Courts have treated it as skill, not cheating: in Uston v. Resorts International (New Jersey, 1982) the state’s supreme court ruled that Atlantic City casinos could not bar a player just for counting, which is why New Jersey casinos rely on shuffling and bet limits instead. Nevada went the other way: casinos there may exclude anyone they like. Devices are different everywhere; Nevada’s statute on cheating devices covers anything that tracks the cards for you. This is general information, not legal advice, and the rules differ by jurisdiction.
Teams and devices
Playing as a team, with spotters counting at minimum bets and a big player called in at high counts, is legal in the same way solo counting is and gets the same response from casinos. Anything electronic that does the counting, from a phone app to a concealed computer, is prohibited: Nevada made such devices a felony in 1985, and other gaming jurisdictions have similar rules.