Knowing how many portions a recipe serves or determining a serving size for a particular food item helps you maintain a healthy weight and plan menus effectively for home cooking or special events. Old-fashioned or home-created recipes may not have portion sizes listed, or you may want to adjust portions to help with weight loss.

Weigh the food item in question. If the item cannot be easily removed from a cooking vessel, like a baked pasta in a casserole dish, weigh a similar empty vessel, then subtract the weight of the empty vessel from the weight of the food item in the vessel.

Look up the individual serving size for the food item or a similar item in a nutrition book or website.

Divide the weight of the food item by its individual serving size. This is the number of servings that the dish serves.

Weigh out one individual portion size. Note the size of the portion.