The European Standard specifies a test method for the determination of the bio-based carbon content in products, based on the ¹⁴C content measurement by Accelerator mass spectrometry (AMS). 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. Part of the ¹⁴C present in products is originating from recent atmospheric CO2. Due to its radioactive decay, it is almost absent from fossil products older than 50 000. The ¹⁴C content may thus be considered as a tracer of products recently synthesized from atmospheric CO2 and particularly of recently produced bio-products. The determination of the biomass content is based on the measurement of ¹⁴C in bio-based products, which allows the calculation of the bio-based carbon fraction. Our Laboratory of the University of Campania “Luigi Vanvitelli” – Dipartimento di Matematica e Fisica, works according to EN16640 for the determination of carbon-based organic content.