One whole avocado generally contains between 200 and 350 calories depending on its size. For example, a medium avocado (about 180-200 grams) typically has 240-290 calories, while a large avocado (about 220 grams) has around 352 calories. A small avocado (around 130 grams) contains about 208 calories. Per 100 grams, an avocado has approximately 160 calories, with most calories coming from healthy fats.