The PubMed Central ID number is not the same as the PubMed number, or PMID, you may have seen in a PubMed search. The PMCID number is displayed in the Citation, Abstract, and AbstractPlus formats in PubMed. However, you can also search for your papers in PubMed Central to find the PMCID.
Note: If your article has an embargo period, the 'Free PMC Article' designation will not show up until the embargo is over. But the PMCID will still be there.
If you already know the PMID, use the Converter to translate one type of ID to another.
NIH Progress Report Requirements
Your progress report to NIH must include the PMCID when citing applicable papers that you author or that arise from your NIH-funded research. For more instructions and examples, visit the NIH help page regarding PMCIDs.