If you have a ADA exchange booklet, you just have to convert how many starches is in the amt. of flour in the recipe, how many fruits would the sugar count for, and on down the recipe with each ingredient. Then add all the starches, all the fruits, all the fats in the recipe and get the total number of each exchange category in the recipe, then divide each exchange category by the number of servings your recipe makes. For example: If your cake recipe had 14 starches in the whole recipe and serves 8, then you would divide 14 by 8 and that would be how many starches a serving of that recipe would have. Then you would divide your fruits by eight and your fats by eight to derive the number of these exchanges in one serving of your recipe. The American Diabetes Assoc. has many booklets on exchanges and the Food Exchange booklet is only about 4 bucks. Hope this helps.