How to Validate and Normalize an ORCID iD
An ORCID iD has 16 characters grouped in fours. Local validation can catch mistyped identifiers before you use a researcher link.
Method
- Remove an orcid.org URL prefix, spaces and hyphens.
- Confirm 15 numeric base digits plus a numeric or X check character.
- Apply the MOD 11-2 algorithm to calculate the expected final character.
- Reformat the valid identifier into four groups and rebuild the canonical orcid.org URL.
Worked example
0000-0002-1825-0097 validates under MOD 11-2.
The canonical URL is https://orcid.org/0000-0002-1825-0097.
Notes
- A valid check digit does not prove that a person controls the ORCID record.
- This local checker does not fetch profile data.
- Open the canonical ORCID record when identity or affiliation verification matters.
- ORCID's checksum can detect many transcription errors, but a valid-looking iD still needs identity verification. Open the ORCID record and confirm the researcher's name and relevant affiliations or works rather than assuming a syntactically valid identifier identifies the right person.
A valid ORCID format does not verify researcher identity
ORCID iDs use four groups of four characters and an ISO 7064 MOD 11-2 check digit. A local validator can normalize the URL or bare identifier and confirm that the check digit is mathematically consistent.
That result cannot tell you whether the ORCID belongs to the researcher you intend to cite. Identity verification requires checking the ORCID record and comparing names, affiliations or works when appropriate.
Normalize the identifier without changing the record meaning
ORCID accepts a canonical https://orcid.org/ form, which is useful for links and data exchange. Removing spaces or a copied URL prefix for validation should not alter the 16-character identifier itself.
If an ORCID record is private or sparse, avoid filling missing identity information from guesswork. The identifier is a pointer to a researcher-controlled record, not a guarantee that every field is public.
Worked example: calculate a real check digit, not just a regex match
Take ORCID's published sample 0000-0002-1825-0097. First remove hyphens to obtain 0000000218250097. Set aside the final 7: the base is the first 15 digits, 000000021825009. Starting at zero, process each base digit using total = (total + digit) × 2. After all 15 digits the total is 1,314. Dividing by 11 leaves remainder 5, so the expected check character is (12 − 5) modulo 11 = 7. This matches the last character and passes the mathematical check.
Try the same process after changing only the final character to 8. The base digits still produce the expected 7, so 0000-0002-1825-0098 fails even though it looks perfectly formatted. This is why a pattern check alone is insufficient: 16 characters separated by hyphens do not establish a valid checksum.
Why X is legitimate and where it can appear
ORCID's example 0000-0002-1694-233X also passes its checksum. The final character X stands for the number ten when the MOD 11-2 algorithm produces that result; it is not a placeholder or a formatting mistake. Uppercase X belongs only at the end, after 15 digits. An X in the middle or an arbitrary letter in any position is invalid.
If you paste an identifier from a PDF, normalize its hyphens and spaces and uppercase the check character before checking. Preserve the four groups when presenting it to readers, preferably as https://orcid.org/ followed by the formatted identifier. Do not 'repair' a failing check digit by guessing a different digit and then silently attributing that number to someone.
Follow a two-stage researcher attribution workflow
Stage one is local integrity: parse the pasted URL or bare ORCID, verify exactly 15 base digits plus one check character, calculate the expected value, and format the canonical link. This catches many accidental transcriptions without a network request. Stage two is record verification: open the canonical ORCID page and assess whether the publicly available works, names and employment or education entries support the author match you need.
A record can be sparse or contain private fields; absence of an affiliation is not proof of fraud. Conversely, a checksum-valid identifier pasted beside a name is not proof of that person's authorship. If the record cannot resolve or evidence conflicts, leave attribution unverified and investigate using the article's own metadata, publisher page or DOI before adding it to a bibliography or staff directory.
Audit a spreadsheet import without confusing validity with ownership
When cleaning a roster of researchers, keep separate columns for the original input, normalized ORCID, checksum status, canonical URL, record opened, and evidence of the proposed author match. For example, an imported https://orcid.org/0000-0002-1825-0097 can normalize to 0000-0002-1825-0097 with checksum status 'pass', while the person-match status remains 'not assessed' until someone actually reviews the record.
Do not automatically merge two people because their names resemble each other or publish private contact details pulled from elsewhere. For citations, a useful final check is to cross-reference the ORCID with the article DOI and author list. Save the date of that check, since public profile metadata can change.
Authoritative references
Primary or authoritative references for the external standard, scoring rule or identifier convention used on this page.
Editorial review and limitations
Continue with the related tools
Use the linked tools for your own inputs and scenarios.
- DOI Link Generator — Normalize one DOI into a canonical doi.org link or extract unique DOI strings from pasted references and research text locally.
- ISSN Checker — Validate an ISSN check digit and normalize an eight-character serial identifier into standard XXXX-XXXX form.
- Bibliography Duplicate Checker — Check one-reference-per-line bibliography text for exact normalized duplicates while preserving the original reference text.