Americans need to know about net carbs, because their usual method of food analysis measures total carbs, including the indigestible fibre( cellulose, or fibre, is a carbohydrate, a polymer of glucose, but we don't have a mechanism for digesting it).. they have to subtract the value for the fibre to find what metabolically available carbs there are. These are the net carbs.
Here we analyse food differently. We list the available carbs separately from the fibre, so we only list net carbs as carbohydrate.
One odd result is that American food tables look different from ours. Carrots to us are about 7.5% carb, but on an American table they are nearly 11% carb. An American would have to subtract the 2.8% fibre to find that the net carbs in raw carrots are about 7.5%.
I'm rounding up the figures, so they don't add up