Published on March 25, 2026
What Card Counting Actually Is
Card counting is not memorising a deck. It is a running tally that tracks whether the cards still to come are richer or poorer in tens and aces than a fresh shoe would be. Blackjack allows it because, unlike a slot, it is dealt from a finite set: every card already seen changes what remains.
The best-known method, Hi-Lo, assigns one of three values to each card as it appears and keeps a single number in your head.
| Cards | Value | What it means |
|---|---|---|
| 2, 3, 4, 5, 6 | +1 | Small cards gone; what remains is better for the player |
| 7, 8, 9 | 0 | Neutral |
| 10, J, Q, K, A | −1 | Big cards gone; what remains is worse for the player |
That figure is the running count. Divide it by the number of decks still unplayed and you get the true count, which is the number that actually matters — a running count of +6 means something very different with one deck left than with six.
What It Is Worth, and What It Costs
A player using perfect basic strategy faces a house edge of roughly half a per cent under common rules. Counting, played well, can turn that into a small edge for the player — typically around one per cent, and only when the count is high enough to justify raising the stake. That is the entire prize: a one-point swing, realised over thousands of hands.
The cost side is where most accounts of counting go quiet. An edge that small needs a bankroll large enough to survive long losing runs, a betting spread wide enough to matter — which is exactly what makes a counter visible — and near-flawless basic strategy underneath it, because a single misplayed hand can give back an hour of advantage.
Is Counting Illegal?
No. Keeping track of cards you can see, using nothing but your own head, is not a crime in any major jurisdiction. Using a device to do it is a different matter and is prohibited outright in many places, Nevada included, where machine-assisted counting is a criminal offence rather than a house rule.
What casinos have instead is the right to decline your business. A land-based venue can ask a counter to leave or bar them from blackjack while welcoming them at every other game, and an online operator can restrict or close an account under its terms. Neither is a legal finding; both are commercial decisions, and they are the reason counting is described as tolerated rather than protected.
Why It Does Not Work in Most Online Blackjack
This is the part that matters most to anyone reading on a phone. Standard online blackjack reshuffles a virtual shoe before every hand, which resets the count to zero each time and removes the entire basis for the technique. Live-dealer tables use physical cards, but most run continuous shuffling machines or cut a large portion of the shoe out of play, which achieves the same thing.
- Reshuffle every hand. No information carries forward; the count is always zero.
- Continuous shuffling machines. Cards return to the shoe as they are played, so the composition never drifts.
- Deep cut cards. Removing a large slice of the shoe from play means the count rarely reaches a level worth betting on.
- Betting-pattern monitoring. The spread that makes counting profitable is also the easiest thing in the world for software to notice.
What Is Worth Doing Instead
Basic strategy is free, learnable in an evening from a printed chart, and worth far more to a casual player than a counting system that the table design has already defeated. It reduces the house edge to a fraction of a per cent, and unlike counting it works on every hand, at every stake, with no bankroll requirement and nothing for the operator to object to.
Then read the rules of the specific table before sitting down. Whether blackjack pays 3:2 or 6:5 changes the house edge by more than counting could ever add: the 6:5 table costs roughly an extra 1.4 per cent, which wipes out the entire theoretical advantage of a skilled counter before a single card is dealt.
Questions About Card Counting
Is card counting legal?
Yes, when done unaided. No major jurisdiction criminalises tracking cards in your head. Using a device is different and is a criminal offence in several places. Separately, and regardless of legality, a casino may refuse service or close an account under its own terms.
Can you count cards in online blackjack?
Not in the standard game: the shoe is reshuffled before every hand, so no information carries from one hand to the next. Live-dealer tables use real cards, but continuous shufflers and deep cut cards remove the effect in most of them.
How much can counting actually win?
Around one per cent of the amount wagered, in the best case, and only with a large bankroll, a wide betting spread and flawless basic strategy. It is a small statistical edge realised over thousands of hands, not a way to beat a casino in an evening.