This Demonstration calculates a golf player's individual handicap based on a series of their round scores and some data about the course on which these scores were obtained. The player's differential is calculated for each one of their scores using the formula differential = (score - course rating) x 113 / (course slope), and the lowest of these values are selected from the 20 most recent scores and displayed in the chart on the left. This selection of the lowest differentials is averaged together and multiplied by 0.96 to calculate the player's overall handicap index.