This European Standard specifies a method for the determination of the bio-based carbon content in products, based on the 14C content measurement. This European Standard also specifies two test methods to be used for the determination of the 14C content from which the bio-based carbon content is calculated: — Method A: Liquid scintillation-counter method (LSC) ; — Method B: Accelerator mass spectrometry (AMS). A third method, Method C: Beta ionization (BI) can also be used for the determination of the 14C content and is described in Annex D (informative) The bio-based carbon content is expressed by a fraction of sample mass or as a fraction of the total carbon content. This calculation method is applicable to any product containing carbon, including bio composites. NOTE This European Standard does not provide the methodology for the calculation of the biomass content of a sample see prEN 16785–1 [5] and prEN 16785–2 [6].