What is the true count in blackjack?

The same running count, different true counts

A running count of +6 at different points of a six-deck shoe.

Why

A running count says how many extra high cards are left, but not how concentrated they are. Six extra tens spread over five decks barely change the next hand; six extra tens in the last deck change it a lot. Dividing by the decks left measures the concentration, and the player’s edge rises roughly in step with it. Unbalanced systems such as KO skip the division by starting the count below zero, at the cost of some accuracy.

Estimating the decks left

Counters read the discard tray: a full deck is about 1.5 cm (half an inch) tall, so a tray with three decks in it means three decks are gone. Most round to the nearest half deck. In this trainer the count strip under the table shows the exact figure, and the countdown drill lets you practice with 1, 2 or 6 decks.

The usual betting convention floors the true count toward zero: +2.8 is bet as +2. Some players round instead; either way, be consistent.

Related questions

• How does card counting work in blackjack?

  You keep a running tally of the cards you see. With Hi-Lo, every 2 to 6 adds one, every ten and ace subtracts one, and 7 to 9 count nothing. A high count means the cards left are rich in tens and aces, which favor the player, so you bet more; a low count favors the dealer, so you bet the minimum.

• Does card counting work with 6 decks?

  Yes. Six- and eight-deck shoes are where most counting happens today. You need the true count rather than the running count, the edge per count is a little smaller than with one or two decks, and how deep the dealer deals before the shuffle decides whether the game is worth playing. A shoe cut at 75% or deeper is beatable; a continuous shuffling machine is not.

• Which card counting system is best?

  Hi-Lo, for almost everyone. It is a balanced level-1 count with a betting correlation of 0.97, its strategy indices are the ones every book and trainer publishes, and it is what professional teams use. Higher-level counts add a few hundredths of a percent of edge and cost speed and errors, which is where real money is lost.

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