Papers with not more than 10% mechanical fiber by total fiber content are classified in the 480254–480258 range, organized by weight. Papers exceeding that threshold fall into the 480261–480269 subheadings. The fiber composition must be determined on a dry-weight basis, and mill certificates or lab analysis are typically used to document compliance.

Standard cut-size copy paper — typically 75–80 g/m², low mechanical-fiber content — generally falls under 480256 (sheets over 360×150 mm) or 480257 (other sheets in the 40–150 g/m² range with not more than 10% mechanical fiber), depending on the sheet dimensions. Confirm the exact dimensions and fiber content against the subheading texts, as the sheet-size thresholds are precise.