Fitday doesn't subtract the (indigestable) fibers from the total carb sum, so in order to get the net carb figures you have to do that manually. If you had 23 carbs acc to Fitday and 5 g fiber, then your actual net carb count is 18 carbs.

I have never included fiber in my carb count. I follow the DANDR way of counting them - wouldn't be much space left for veggies otherwise. Some people seem to count "total carbs" (incl fiber), but I can't see the point, since fiber passes through our body, don't carry any energy and helps digestion/bowel movements. It would be like counting cardboard...

/gil