Teff flour is relatively low in carbs, but it also contains a significant amount of fiber, which means that the carb content of teff flour can vary depending on the brand you purchase.  For example, one cup of teff flour from Bob's Red Mill contains 29 grams of carbohydrates, but 8 grams of fiber, for a net carb content of 21 grams.  This means that teff flour is moderately high in carbs.