ISO 16620-4:2016 specifies a method of determining the biobased mass content in plastics products, based on the radiocarbon analysis and elemental analysis. ISO 16620-4:2016 is applicable to plastic products and plastic materials, polymer resins, monomers or additives, which are made from biobased or fossil-based constituents. This method is applicable, provided that the plastic product contains carbon element and that a statement giving its elemental composition and its biobased mass content is available.