The amount of calories in a 7-11 Slurpee depends on the flavor and size of the drink. The flavors available vary by region, and some are only offered for a limited time. Sizes vary from 8 ounces to 32 ounces.
For example, an 8-ounce Dr Pepper Slurpee has 150 calories. Meanwhile, an 8-ounce Coca Cola Classic Slurpee has 65 calories. A 32-ounce Slurpee has four times as many calories as the 8-ounce version. So, in the 32-ounce sizes, the Dr Pepper Slurpee would have 600 calories, and the Coca Cola Classic Slurpee would have 260 calories. Other flavors and sizes also vary in calorie content.