One cake weighs ~9 g at 387 kcal per 100 g — about 34.8 kcal per cake. Rice cakes are a rare snack where a clean per-piece count actually tracks accurately, since size is standardized.
How should I track Rice cakes, brown rice, plain, unsalted?
Rice cakes, brown rice, plain, unsalted is high in magnesium. When it comes to Rice cakes, brown rice, plain, unsalted, weighing beats counting every time. Snack pieces vary in size, and a handful from a bag can easily be 50–100% more than the label serving. Research (Almiron-Roig et al., Appetite 2013) shows that people consistently underestimate portions of calorie-dense snacks. Another common trap: multi-serving packages. The label might show 150 calories "per serving," but if the bag contains three servings, you are really looking at 450 calories. Always check whether values are per piece, per serving, or per package.