Use the Article 24 volume basis
For grouped, transport and e-commerce packaging, PPWR defines empty space against the volume of sales packaging contained inside the outer packaging, and filling materials still count as empty space. Sales packaging follows a separate minimisation rule without the Article 24(1) fixed 50% cap.
This calculator is a planning aid. The Commission methodology required by Article 24(2) can change how the grouped/transport/e-commerce ratio must be assessed, so verify the current implementing act before treating a result as a conformity conclusion.