According to Fit Today, one shrimp with cocktail sauce contains around 22 calories. The total calories of a shrimp cocktail will depend on the number of shrimp and amount of sauce. Count the shrimp, and multiply by 22 for total calorie count.
Shrimp cocktails usually contain 5-7 shrimp, which would put the total calorie count to 110-155 calories. Shrimp are a good source of lean protein. Of the calories, 56 percent are from protein, 33 percent are from carbohydrates and 11 percent from fat, according to Fit Today. Of the fat content in a shrimp cocktail, the majority is polyunsaturated fat. Use low-fat or sugar-free ketchup to make a low-calorie version of cocktail sauce.