Vancouver Citation Checker
Paste a Vancouver reference list and get each likely departure from NLM style flagged — numbering by first citation, Surname AB names, six authors before et al., sentence-case titles, journal abbreviations without periods and the Year;Volume(Issue):Pages block — each with a fix to copy. Free, no sign-up, and nothing is uploaded.
One reference per line, or wrapped lines under their number. The check runs in your browser — nothing is uploaded.
Paste a Vancouver reference list to check it.
What this checker looks for
- Numbering in citation order, with no gaps, repeats or numbers out of sequence.
- Authors as Smith JA — surname, then initials with no periods or spaces — separated by commas with no “and”: the first six names, then et al.
- Article titles in sentence case, without quotation marks.
- Journal abbreviations without periods: N Engl J Med.
- The block Year Mon Day;Volume(Issue):Pages with no spaces, three-letter months and shortened page ranges (284-7).
- DOIs written doi: 10.xxxx, and a period at the end of each reference.
- The same source listed twice, and lists sorted A–Z instead of by first citation.
It does not check journal abbreviations against the NLM Catalog, and journals that follow the ICMJE recommendations still differ in small ways — some print full page ranges or list every author. Every finding is a likely issue to review, not a verdict; your list is never rewritten for you.
How to Use the Vancouver Citation Checker
- Paste your reference list. Keep the numbers — 1. or [1] — with one reference per line; a wrapped line stays with the number above it.
- Fix the list-level findings first. A gap in the numbering, or a list in alphabetical order, means the numbers no longer follow the order of first citation.
- Go through each reference. Copy the suggested fragment — a corrected author element, the locator block without spaces, the three-letter month — and follow the link to the rule behind it.
- Check what the tool cannot. Look each journal abbreviation up in the NLM Catalog and confirm each source’s details.
Which Rules Vancouver Style Follows
Vancouver is the numbered style of the International Committee of Medical Journal Editors (ICMJE). Its recommendations ask for references numbered consecutively in the order they are first mentioned in the text, journal titles abbreviated as MEDLINE abbreviates them, and entries formatted like the U.S. National Library of Medicine’s sample references and its manual, Citing Medicine (2nd ed.). NLM’s standard journal reference:
Halpern SD, Ubel PA, Caplan AL. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002 Jul 25;347(4):284-7.
| Element | Vancouver form | Flagged when |
|---|---|---|
| Authors | Halpern SD, Ubel PA | periods (Halpern S. D.), a comma before the initials (Halpern, SD), or initials first (S. D. Halpern) |
| Between authors | commas only | “and” or “&” before the last name |
| Seven or more | the first six, then et al. | all seven listed, or et al. after fewer than six |
| Article title | sentence case, no quotation marks | in quotation marks, or every main word capitalized |
| Journal | N Engl J Med — no periods | N. Engl. J. Med. |
| Date and locator | 2002 Jul 25;347(4):284-7 | spaces around ; ( or :, July or Jul. |
| Page range | 284-7 — repeated digits dropped | 284-287 (worth a look) |
| DOI | doi: 10.1136/bmj.a2752. | DOI: 10.… or doi:10.… with no space |
| Final period | every reference | missing, unless the reference ends with a URL |
Sources: NLM, Samples of Formatted References for Authors of Journal Articles; Citing Medicine, 2nd ed., as summarized by university library guides; ICMJE Recommendations, Preparing a Manuscript for Submission.
Two rules vary between journals that call themselves Vancouver. NLM’s samples list six authors before et al., but MEDLINE itself now lists every author and some journals ask for all of them; and Citing Medicine shortens page ranges (123-125 becomes 123-5) while many journals print them in full. The checker marks both as Worth a look rather than Likely issue — your journal’s instructions for authors decide.
Worked Example
Try a sample loads four of NLM’s own examples, two of them with mistakes put in. The result is 10 likely issues to review across 4 references:
- The list skips 4: the numbers run 1, 2, 3, 5.
- Reference 2 lists all eight authors. The fix keeps the first six: Rose ME, Huerbin MB, Melick J, Marion DW, Palmer AM, Schiding JK, et al.
- Reference 3 collects seven findings: commas and periods in the names (the fix is Forooghian F, Yeh S, Faia LJ, Nussenblatt RB.), a title in quotation marks and in Title Case, the dotted journal Arch. Ophthalmol., and a locator with spaces, a full month name and a full page range — fixed together as 2009 Feb;127(2):179-86.
- Reference 5 writes doi:10.1136/bmj.a2752 with no space and no closing period; NLM writes doi: 10.1136/bmj.a2752.
Reference 1, NLM’s Halpern example, passes as printed.
What the Checker Leaves to You
- Abbreviations. It catches periods in a journal abbreviation but cannot tell whether the abbreviation itself is NLM’s; check it in the NLM Catalog or with the Journal Abbreviation Finder.
- Proper nouns in titles. The Title Case test fires only when every main word is capitalized, so a sentence-case title with a few proper nouns passes, and a wrongly capitalized ordinary word may too.
- Books, chapters and web pages. These are checked for authors, numbering, the DOI and the final period; their place, publisher and date elements are not.
- Facts. A wrong year, volume or page range looks just like a right one. Check each reference against PubMed or the article itself.
Frequently Asked Questions
- How many authors do you list in Vancouver style?
- NLM’s sample references list every author up to six and, with more than six, the first six followed by et al. NLM notes that its own database now lists all authors, and some journals ask for every name, so follow your journal’s instructions if they differ.
- Do Vancouver references use full stops after initials?
- No. Initials follow the surname with no periods and no spaces — Halpern SD — and authors are separated by commas, with no “and” before the last one. The period after the final name closes the author element.
- How are page numbers written in Vancouver?
- Citing Medicine drops the leading digits that the last page repeats: 123-125 becomes 123-5 and 1563-1571 becomes 1563-71, while a range with nothing to drop, such as 391-402, stays whole. Many journals print full ranges instead, so the checker treats this as worth a look rather than an error.
- Where do I find the correct journal abbreviation?
- In the NLM Catalog, the MEDLINE list the ICMJE recommendations point to. NLM abbreviations carry no periods: N Engl J Med, Arch Ophthalmol, Proc Natl Acad Sci U S A. A one-word title, such as Lancet or Hypertension, is not abbreviated.
- Is Vancouver the same as AMA style?
- No, though they look alike. Both number references by first citation and write names as Surname AB, but AMA lists three authors before et al. rather than six, italicizes journal names, gives full page ranges, writes the DOI as doi:10.… with no period after it, and uses superscript numbers in the text. Check an AMA list with the AMA citation checker.
- Should a Vancouver reference include the DOI or PubMed ID?
- NLM’s samples show both as optional additions after the locator — doi: 10.1136/bmj.a2752. and PubMed PMID: 19129307. Include them if your journal asks for them; the checker looks only at how the DOI is written.
- Is my reference list uploaded anywhere?
- No. The checker runs entirely in your browser; nothing you paste is sent to a server or stored.