To calculate the true count in card counting, you first track the running count by assigning values to cards as they are dealt, typically using the Hi-Lo system. Low cards (2-6) are counted as +1, high cards (10-Ace) as -1, and mid-range cards (7-9) as 0. After determining the running count, you estimate the number of decks remaining in the shoe. The true count is then calculated by dividing the running count by the number of decks left. The true count provides a more accurate measure of the ratio of high to low cards, helping you adjust your betting strategy—higher true counts signal an advantage for the player, while lower counts indicate a deck favoring the dealer.