Section 1 specifies a method for the determination of the gravimetric thickness of a sample of plastics film or sheeting. Test specimens of 100 cm2 shall be cut at positions across the width of the sample. The thickness is calculated from measurements of their mass, area, and density. This method is of special value, when mechanical scanning is not sufficiently precise, particularly in the case of embossed sheeting. Section 2 specifies a method for the determination of the average gravimetric thickness and if required, the yield (area per unit mass) of a roll of plastics films or sheeting. Calculation from measurements of length, average width, net mass of the roll and density of the film or sheeting.