The number of calories in a peanut butter sandwich can depend on several factors, such as the type of bread and the kind and amount of peanut butter used. A sandwich made from two slices of whole wheat bread and two tablespoons of smooth peanut butter with salt contains 327 calories, according to Self Nutrition Data.
It also contains 30 grams of carbohydrates, 18 grams of fat, 6 grams of dietary fiber and 15 grams of protein. The two tablespoons of peanut butter account for 191 calories, according to the United States Department of Agriculture Nutrient Database. Because this sandwich has 327 total calories, the two pieces of whole wheat bread are then 136 calories. Using more peanut butter will increase the number of calories in one serving.