Card counting does not work in online blackjack. Not against RNG tables, which shuffle every hand, and not meaningfully against live dealer tables, which cut away too much of the shoe. This page explains exactly why, because understanding the why is the most useful blackjack education there is.
What counting actually is
Counting tracks the ratio of high cards (tens, aces) to low cards remaining in the shoe. A shoe rich in tens favours the player: blackjacks (paying 3:2) come more often, and dealer stiff hands bust more. Counters raise bets when the ratio tilts favourable and shrink them when it does not. Done perfectly in a deep-dealt physical shoe, it yields a player edge of roughly 0.5–1.5%.
Three conditions make it work: cards leave play after dealing (memory), enough of the shoe gets dealt before reshuffle (penetration), and bet spreads go unpunished (tolerance). Online removes them in order.
Why RNG tables are immune
RNG blackjack reshuffles the full shoe every hand. No cards leave play; every round starts from the identical composition. There is nothing to count — the count resets to zero by design before each deal. This is not anti-counter enforcement; it is simply what a software shuffle is.
Provably fair versions at crypto casinos let you verify exactly this: each hand derives from a fresh seeded shuffle, checkable after the fact.
Why live dealer tables don't pay either
Live tables deal from physical shoes, so a count technically exists. Two implementation choices kill its value:
1. Penetration. Studios typically cut 50% or more of an eight-deck shoe out of play. Favourable counts concentrate deep in a shoe; cutting the back half removes most of the situations a counter waits for. 2. Continuous shuffle machines. Many live tables return cards to a CSM continuously — the RNG condition recreated in hardware.
If you want the math: counter profit scales steeply with penetration. At 75% penetration an expert with a 1–12 bet spread earns a real edge; at 50%, expected value collapses to roughly nothing after bet-spread costs — the favourable tail of the shoe simply never arrives.
What this means in practice
1. Anyone selling online counting systems is selling fiction. The shuffle physics above are not disputed. 2. Basic strategy is the ceiling online. The chart gets you to ~0.5% house edge; no legal technique online improves on it. 3. The game is entertainment priced at that 0.5%. Bet sizing systems do not change it — see bankroll management for what sizing actually controls (variance, not edge).