Gambling terms, explained straight

Advantage Play & Game Integrity

Card counting machine

A card counting machine is a device used to assist a blackjack player in counting cards by tracking exposed cards to maintain a running count.

Applies to
Blackjack and other card games where exposed cards can be tracked for advantage play24
Legality
Card counting is not illegal under British law or U.S. law, provided no external device assists the player1

Key points

  • The device helps a player keep a running count of high and low cards as they are exposed, indicating when the remaining deck favours the player23.
  • Using a card counting machine is distinct from mental card counting; using an external device to assist may be illegal even where mental counting is not1.

Where this term is used

Not the same as

  • Card counting — the general mental strategy, not a physical device
Advantage play Card counting The mental strategy of tracking cards to gain an advantage in blackjack. Advantage play Card counting machine blackjack The game context of blackjack counting, not a machine itself. Advantage play Blackjack card counting The specific application of card counting to the game of blackjack. Advantage play KO card counting An unbalanced card counting system used in blackjack. Advantage play Hi-lo card counting A balanced card counting system that assigns values of +1, 0, and -1 to cards. Advantage play Dice control Dice control is a disputed craps technique where a player sets the dice in a chosen orientation and throws them in a …

Sources

  1. Card counting en.wikipedia.org Provides the definition of card counting and the legal status of using devices.
  2. Blackjack en.wikipedia.org Supports the application of counting devices to blackjack and multi-deck contexts.
  3. Card Counting in Blackjack - Introduction & Basics wizardofodds.com Explains how a counting device helps track the running count.
  4. Blackjack - Counting Cards - Wizard of Odds wizardofodds.com Confirms the use of devices in blackjack counting and the house edge context.

Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.

Written and maintained by Ellis Warrender, writer and maintainer.

Last updated 28 July 2026. Spotted an error? Tell me and it gets fixed and logged on the corrections page.