Carbs in Sourdough Bread. The favorite choice for the term Sourdough Bread is 1 medium slice of Sour Dough Bread which has about 13 grams of carbohydrate.The total carbohyrate, sugar, fiber and estimated net carbs (non-fiber carbs) for a variety of types and serving sizes of Sourdough Bread is shown below.View other nutritional values (such as Calories or Fats) using the filter below: Calories | Total Carbs | Total Fats | Protein | Sodium | Cholesterol | Vitamins.read-Sourdough Roll (San Francisco Soup Company). Please note that some foods may not be suitable for some people and you are urged to seek the advice of a physician before beginning any weight loss effort or diet regimen.