Biobased carbon content of paint according to ASTM D6866 indicates how much of the samples total organic carbon content is from renewal resources. Method includes removal of inorganic carbon prior to testing. Biobased carbon content according to this method does not indicate how much of the sample weight is biobased, it only refers to organic carbon. The method is based on analysing different carbon isotopes in the sample using accelerator mass spectrometry (ASM).