Common questions about card counting, the math behind it, and what to expect in practice.
The basics
Is card counting illegal?
No. In every US jurisdiction and most other legal gambling jurisdictions, card counting using only your brain is completely legal. Casinos are privately owned businesses, though, so they can refuse service to anyone they suspect of counting — even without proof. Getting caught counting typically means being asked to stop playing blackjack or, in some venues, being “trespassed” (banned from the property). You won’t be arrested.
How much can a card counter actually make?
A skilled counter with good rules, a bet spread of 1-to-12 or wider, and decent penetration can carry a player edge of around 0.5–1.5%. At $25 average bet size and 80 hands per hour, that’s roughly $10–$30 per hour on average. But variance is enormous — the hourly standard deviation at those stakes is several hundred dollars — so you need tens or hundreds of hours before the edge shows through the noise. Our bankroll calculator runs your specific numbers.
How long does it take to learn?
Running count on Hi-Lo: a week or two. True count conversion: another week or two. Counting at full casino speed while playing basic strategy correctly: one to three months. Counting without being noticed, with an appropriate bet spread, in a hostile environment: substantially longer, and something some people never get good at. Our trainer is designed to compress the early skill-building phase.
What’s “basic strategy” and do I need it?
Basic strategy is the mathematically optimal play for every combination of your hand and the dealer’s up card, assuming no knowledge of remaining cards. Yes, you need it — card counting only shifts the correct play in a small number of situations (the “Illustrious 18” and a few others). For every other hand, basic strategy is what you do. See our strategy charts.
The math
What is the “true count” and why do I need to convert?
The running count tells you how many high cards versus low cards have come out, in absolute terms. But a running count of +6 means different things depending on how many decks are left: +6 with one deck remaining is a huge player edge; +6 with six decks remaining is almost nothing. The true count (running count ÷ decks remaining) normalizes this so the number always means the same thing.
How much does penetration matter?
A lot. Penetration is the fraction of the shoe dealt before shuffling. Deeper penetration means more hands played at high true counts, which is where counters make their money. A game with 75% penetration might be profitable; the same game with 50% penetration typically isn’t. This is the single biggest reason online blackjack isn’t countable.
What are the Illustrious 18?
A set of 18 playing-strategy deviations that a counter should make based on the true count — situations where the correct play changes based on what’s left in the deck. The most famous is insurance: you should always take insurance when the true count is +3 or higher. Most of the edge from playing deviations comes from a small number of these; the full 18 captures nearly all of it.
What’s “risk of ruin” and what’s a reasonable number?
Risk of ruin (RoR) is the probability you lose your entire bankroll before variance works in your favor. At a 5% RoR, roughly one counter in 20 goes broke before profiting. Most serious counters target 1–5% RoR, which typically requires a bankroll of 200–300 units (average bets). Our bankroll calculator computes this for your specific situation.
Practical play
Will casinos really kick me out for counting?
Yes — if they catch you. Pit bosses are trained to watch for tells: sudden bet increases correlated with deck composition, intense concentration, not drinking, lip movement. A sophisticated counter controls all of these; a beginner controls none of them. What actually happens varies by venue: tribal casinos often just back you off blackjack; Las Vegas casinos may ban you from blackjack or from the whole property; some jurisdictions track shared “counter watch” databases.
Can I count cards in a team?
Yes, and team play was historically how most large-scale card counting happened (famously the MIT Blackjack Team). The advantage of a team: you separate the “spotter” (who tracks the count at small minimum bets) from the “big player” (who only sits down when the count is already positive and bets big). This looks much less suspicious than one person spreading their own bets. The disadvantage: it requires trust, coordination, and a shared bankroll, which are hard problems.
What counting system should I start with?
Hi-Lo. See our counting systems comparison for why. It’s the right answer for almost everyone.
Can I count at the poker room or at other casino games?
No. Counting is specific to blackjack (and its close cousins, like Spanish 21 with adjustments). Poker is a different game entirely — you’re not playing against the house, and the skill dimensions are different. Other traditional casino games (roulette, craps, baccarat) have no memory between outcomes, so there’s nothing to count.
Online play
Can I count cards at online casinos?
Short answer: no, for practical purposes. Long answer: we wrote a whole page on this.
Why does your site have casino affiliates if online counting doesn’t work?
Because people play online for reasons other than counting. Low-edge games, bonus clearing, live dealer as practice — there are legitimate reasons to have an online casino account even if you’re primarily a live-game counter. We recommend operators based on general play quality, and we’re transparent about what we are and aren’t claiming.
Is online blackjack rigged?
In licensed jurisdictions with regulated operators, no. Legitimate online casinos use certified RNGs that are audited for fairness. The house edge on basic-strategy blackjack at a licensed online casino is what it says it is — usually 0.5% or so. That’s not rigged, that’s just how the game’s designed. (Unlicensed offshore operators, on the other hand, can do whatever they want. Use licensed casinos.)