BLT sandwich calories content may vary depending on the bread that you use. If you use whole wheat bread, the total calorie content for 1 serving unit is 339 calories and half serving contains 169 calories. For classic BLT sandwich, the total calories content is 517. Most of these calories came from the fat content of the sandwich which 64% of the whole BLT sandwich. The rest of the nutritional contents are cholesterol, sodium, protein and carbohydrates. Because of the calories in this sandwich, you may want to refrain from eating them on a regular basis or find a healthier alternative for your ingredients. For more reference on calories content, please refer to http://www.food.com/recipe/classic-blt-sandwich-129615.