how many calories in a slice of watermelon
1 Calories in a slice of watermelon, a sixteenth of a whole, weighing approx 10.1 oz - 86. 2  1 oz of watermelon flesh has 9 watermelon calories in. 3  1 g of watermelon flesh has 0 calorie. 4  110 g of watermelon flesh has 30 watermelon calories.