Direct comparison
PubMed vs. PubMed Central (PMC)
PubMed indexes citations and abstracts; PMC holds full text. What's actually in each, and how NIH's Public Access Policy links a PMID to a PMCID.
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How do PubMed, PubMed Central (PMC) compare side by side?
The table below compares PubMed, PubMed Central (PMC) across 10 procurement-relevant dimensions, from what it is through resolution url.
Side-by-side comparison
| Dimension | PubMed | PubMed Central (PMC) |
|---|---|---|
| What it is | A citation and abstract search database/index | A full-text digital archive |
| What’s actually inside | Citations, abstracts, MeSH terms and metadata — not the article text itself | The deposited full text: published version, accepted author manuscript, or preprint |
| Approximate size | 40 million+ citations and abstracts | 10 million+ full-text article records (11,327,616 as of FY2025) |
| Where its content comes from | MEDLINE-indexed journals, PMC deposits, and the NLM Bookshelf | Publisher deposit, NIH Manuscript Submission (NIHMS), and funder/international collaborations |
| Managing body | National Library of Medicine (NLM/NCBI) | National Library of Medicine (NLM/NCBI) — same parent, separate database |
| Does every record in one appear in the other? | No — most PubMed citations have no PMC full-text deposit | Mostly, but not always — PMC also holds some preprints that may not carry a separate PubMed citation |
| Its own identifier | PMID — a plain number, assigned to nearly every citation | PMCID — "PMC" prefix plus digits, assigned only once full text is deposited |
| Role in NIH Public Access Policy compliance | Indexing alone does not satisfy the policy | Deposit here is what the policy actually requires; the PMCID is the compliance identifier |
| Typical use case | Search and discover the biomedical literature | Read or download the full open text of a specific article |
| Resolution URL | pubmed.ncbi.nlm.nih.gov/{PMID} — citation and abstract | pmc.ncbi.nlm.nih.gov/articles/{PMCID} — full text |
Common questions
Common questions about PubMed vs PubMed Central (PMC)
Is PubMed Central the same website as PubMed?
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No. They’re both run by the National Library of Medicine and are easy to confuse, but PubMed is a citation/abstract search index and PubMed Central (PMC) is a separate full-text archive. A PubMed search can return a citation with no corresponding PMC deposit.
If an article is in PubMed, is the full text automatically in PMC?
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No. Most PubMed-indexed articles are never deposited into PMC unless a funder mandate (like NIH’s) or the publisher’s own open-access program puts them there. PubMed indexing and PMC deposit are two separate events.
Why does my NIH-funded paper have a PMID but no PMCID?
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A PMID is assigned automatically once a citation is indexed in PubMed. A PMCID is only assigned after the full text is actually deposited into PMC. If that deposit hasn’t happened — or wasn’t initiated — there’s no PMCID to cite yet, and the NIH Public Access Policy requirement isn’t satisfied by the PMID alone.
Can PMC contain something that isn’t in PubMed?
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Yes, in some cases. PMC also holds preprints that are explicitly labelled as not yet peer-reviewed, which can sit outside standard MEDLINE/PubMed indexing criteria.
