Gambling terms, explained straight

Advantage Play & Game Integrity

Blackjack odds with card counting

Blackjack odds with card counting describes how a player can gain a statistical edge by tracking the ratio of high to low cards remaining in the deck.

High-low tag values
2–6: +1, 7–9: 0, 10–A: −12
True count formula
Running count ÷ decks remaining34
Typical player advantage
0.5% to 1.5% under current rules32

Key points

  • The counter raises bets when the true count is high, because the deck contains more tens and aces than usual.13
  • Basic strategy alone gives the house an edge of about 0.5%–1%; card counting can flip that to a small player edge.26
  • Casinos may ban counters but counting without a computer or cheating device is not illegal.35

Where this term is used

Not the same as

Advantage play Blackjack card counting Explains the same concept under its more common name. Advantage play Card counting Covers the general technique used across blackjack and other games. Advantage play Blackjack card counting bot Describes automated software that counts cards, which is typically prohibited. Advantage play Hi-lo blackjack card counting Details the most popular card-counting system for blackjack. Advantage play Hi-lo card counting Explains the hi-lo system in a broader context. Advantage play Hi-lo count blackjack Hi-lo count blackjack is a card-counting method

Sources

  1. Card counting en.wikipedia.org Provides the definition and general description of card counting.
  2. Blackjack en.wikipedia.org Supplies the high-low tag values, basic strategy edge, and player advantage range.
  3. Card Counting in Blackjack - Introduction & Basics wizardofodds.com Gives the true count formula and the typical counter advantage.
  4. Introduction to the High-Low Card Counting Strategy wizardofodds.com Also supports the true count formula.
  5. Blackjack - Counting Cards - Wizard of Odds wizardofodds.com Clarifies the legality of card counting.
  6. Basic Strategy for Some Simplified Blackjack Variants arxiv.org Provides the basic strategy edge figure.

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.