The cellulose analysis results of four feedstocks and Avicel obtained by a one-step/two-step hydrolysis method were compared to the conventional cellulose assay according to Updegraff. Slightly lower cellulose levels were observed for Avicel (97%), corn stover (97%), poplar (96%), and Miscanthus (94%) but for pine the amounts were almost identical (101%). Despite these differences, the one-step/two-step method can be seen as a true alternative to the more labor-intensive Updegraff method. (C) 2014 Wiley Periodicals, Inc.