There are approximately 72 calories in one medium size apple. Includes: 148 mg of potassium, 2% Vitamin A, 10% of vitamin C, 1% of iron, & 1% of calcium. These percentages based on a 2000 calorie diet. Two of the 72 calories are from fat. It also contains 19.06g carbohydrates, 3.3 grams of fiber, 14.34 grams of sugar and 1 mg of sodium.