BMJ Open Formatting Requirements: Complete Author Guide

BMJ Open publishes several article types with distinct word limits. The editorial system checks these during submission.

Word counts exclude the abstract, references, figure legends, and table content. BMJ Open doesn't impose a strict limit on figures, tables, or references, which is more generous than most journals. That said, don't go overboard. If your paper has 15 figures, consider moving some to the supplementary file.

Protocol papers are a distinctive feature of BMJ Open. Publishing your study protocol before collecting data provides a citable record of your planned methods, helps prevent outcome reporting bias, and can count as a publication. BMJ Open is one of the most popular venues for protocol publication.

BMJ Open requires structured abstracts for all research articles, limited to 300 words. The required headings are:

For Original Research:

• Objectives

• Design

• Setting

• Participants

• Interventions (if applicable)

• Primary and secondary outcome measures

• Results

• Conclusions

This is more granular than most journals. Where other journals combine design information into a single "Methods" heading, BMJ Open separates Design, Setting, Participants, and Interventions into individual sections. Each should be 1-2 sentences.

Objectives should state exactly what the study aimed to do. One sentence is usually enough.

Design specifies the study type: randomized controlled trial, prospective cohort, cross-sectional survey, etc. Include the time period.

Setting describes where the study was conducted: primary care, hospital, community, country.

Participants includes the number enrolled, key demographics, and inclusion criteria.

Results should report primary outcomes with numbers, effect sizes, confidence intervals, and P values. Be specific.

Conclusions should be limited to what the data support. BMJ Open reviewers are particularly attentive to conclusions that overreach the data, and the open review process means any reviewer criticism of your conclusions will be publicly visible.

BMJ Open requires a "Strengths and Limitations" box immediately after the abstract. This must contain 3-5 bullet points that honestly assess your study's strengths and limitations.

This is unusual. Most journals ask authors to discuss limitations in the Discussion section, but BMJ Open puts them front and center. Don't treat this as a throwaway. Reviewers compare your self-assessment against their own evaluation, and a paper that omits obvious limitations will draw criticism in the open review.

Good Strengths and Limitations statements are specific. "Large sample size" is vague. "Population-based cohort of 45,000 participants with 10 years of follow-up" is informative. Similarly, "potential for confounding" is generic. "Unable to adjust for socioeconomic status due to data limitations" is honest and specific.

BMJ Open requires a title page with:

• Full title (informative and specific)

• All author names with highest academic degrees

• Institutional affiliations

• Corresponding author's contact details

• Word count of body text and abstract (separately)

• Number of figures and tables

• Keywords (3-5 from MeSH terms)

BMJ Open also requires:

• Contributor statement: specific contributions for each author using ICMJE criteria

• Funding statement: all funding sources and grant numbers

• Competing interests declaration: must be completed for all authors

• Patient and public involvement statement: describe how patients/public were involved in the research design, conduct, or dissemination (or state that there was no involvement)

The Patient and Public Involvement (PPI) statement is a BMJ Group-wide requirement and is taken seriously. If patients weren't involved in your study design, say so directly. Don't fabricate involvement.

BMJ Open doesn't impose a strict limit on the number of figures and tables. However, the expectation is that display items should be necessary and well-designed.

Figure requirements:

• Minimum resolution: 300 DPI for photographs, 600 DPI for line art

• Accepted formats: TIFF, EPS, JPEG, or PDF

• Maximum file size: 5 MB per figure (larger files can be uploaded as supplementary)

• Color figures are free (open access journal)

• Each figure uploaded as a separate file during submission

• Multipanel figures should be clearly labeled (A, B, C)

Table requirements:

• Created in Word using the table editor

• Every column must have a header

• Use horizontal rules only (top, bottom, below headers)

• No vertical lines or cell shading

• Footnotes use superscript symbols or lowercase letters

• All abbreviations defined below the table

• Tables placed at the end of the manuscript, each on a separate page

For systematic reviews, PRISMA flow diagrams are expected as Figure 1. Forest plots should include heterogeneity statistics (I-squared, chi-squared P value) and individual study weights.

BMJ Open uses standard Vancouver (NLM) reference formatting. References are numbered consecutively as they appear in the text and cited using superscript numbers.

Key formatting rules:

• Superscript citation numbers in text, placed after punctuation

• List all authors up to 6; for 7 or more, list the first 6 followed by "et al"

• Journal titles abbreviated per NLM/Medline standards

• Include volume, page range (or article number for e-publications), and year

• DOIs encouraged for all references

• Include PMIDs where available

Example reference:

1 Smith AB, Jones CD, Williams EF, et al. Patient engagement in primary care quality improvement: a cluster randomized trial. BMJ Open 2025;15:e098765. doi:10.1136/bmjopen-2025-098765

Note that BMJ Open uses "e" article numbers rather than page ranges for its own articles. When citing other BMJ Open papers, use the article number format.

Reference managers with BMJ-specific styles are available from BMJ Author Hub. Both Zotero and EndNote have compatible output styles. Verify your style is set to Vancouver format before exporting.

Worked reference-manager check:

Wrong author-date export: Smith, A. B., Jones, C. D., Williams, E. F. Patient engagement in primary care quality improvement. BMJ Open. 2025;15:e098765.
BMJ Open target: Smith AB, Jones CD, Williams EF, et al. Patient engagement in primary care quality improvement: a cluster randomized trial. *BMJ Open* 2025;15:e098765. doi:10.1136/bmjopen-2025-098765

The common failure is not the article number itself. It is a reference-manager export that leaves APA-style author punctuation, Word footnotes, or EndNote field codes in the manuscript. BMJ Author Hub says references should be part of the main text document, not inserted as Word footnotes or live citation fields.

BMJ Open publishes supplementary material online alongside the article. All supplementary files undergo peer review.

Supplementary material can include:

• Additional tables and figures

• Extended methods and statistical analyses

• Questionnaires and survey instruments

• Interview topic guides (for qualitative research)

• Data collection forms

• Additional sensitivity analyses

Supplementary files are labeled as "online supplemental file 1," "online supplemental figure 1," etc. They can be submitted as Word, PDF, Excel, or other standard formats.

For systematic reviews, the full search strategy for each database should be included as supplementary material. For qualitative studies, the interview guide or focus group schedule should also be supplementary.

BMJ Open prefers Microsoft Word for submissions. The journal uses ScholarOne, and the production workflow is built around Word and XML.

Word submissions:

• 12-point Times New Roman or Arial

• Double-spaced throughout

• Continuous line numbering (this is mandatory, not optional)

• 1-inch margins on all sides

• Page numbers on every page

LaTeX submissions:

• Accepted but not the standard workflow

• Submit compiled PDF plus all source files

• Use a standard article class (no BMJ-specific template is provided)

• Will be converted to Word/XML during production

• Expect some formatting adjustments during copyediting

For most BMJ Open submissions (clinical trials, observational studies, public health research), Word is the practical choice. LaTeX offers no meaningful advantage for the types of manuscripts BMJ Open typically publishes.

Use BMJ's current formatting your paper page as the starter-file reference before upload. The practical template is not a decorative .docx; it is a Word manuscript that follows BMJ's order, heading hierarchy, table handling, reference handling, and separate upload-file requirements.

BMJ Open's open peer review policy means:

• Reviewer names are published alongside accepted articles

• The full review history (reviewer reports, editor decisions, author response letters) is published online

• Reviewers know their identity will be revealed if the paper is accepted

• Authors should write response letters knowing they will be public

This has practical implications for formatting. Your response to reviewers should be professional, detailed, and well-organized. Use a point-by-point format addressing each comment. These responses become part of the permanent published record.

BMJ Open has several unique requirements beyond the standard formatting rules.

1. EQUATOR checklists are non-negotiable. This is the single most common reason for desk rejection at BMJ Open. If you don't upload the right checklist, your paper won't enter review. Period.

2. Strengths and Limitations box is mandatory. This appears immediately after the abstract and is separate from the Discussion section. It must contain 3-5 bullet points.

3. Patient and Public Involvement statement is required. Even if patients weren't involved, you must include a statement. This is increasingly common across BMJ journals.

4. Open review changes the dynamic. Knowing that reviews will be published tends to produce more constructive and thorough reviews. But it also means your response letters need to be polished. Typos and terse responses will be permanently visible.

5. Protocol papers are a strong option. If you're planning a clinical trial or systematic review, consider submitting the protocol to BMJ Open before starting data collection. This establishes your methods publicly and can prevent accusations of outcome switching.

The most frequent triggers for administrative return at BMJ Open:

• Missing EQUATOR checklist (most common reason by far)

• Missing Strengths and Limitations box

• Abstract exceeding 300 words

• Missing Patient and Public Involvement statement

• Abstract using wrong headings (e.g., "Methods" instead of "Design")

• Checklist page numbers that don't match the manuscript

• No line numbering in the manuscript

EndNote, Zotero, Paperpile, and Word can all make the file look polished while leaving BMJ Open-specific issues unresolved. The highest-risk pitfall is a reference list that displays numbered citations but still contains Word citation fields, EndNote codes, APA-style punctuation, or footnote/endnote references. BMJ's formatting guidance expects references inside the main text document, not as footnotes or hidden citation objects.

The second pitfall is treating the EQUATOR checklist as an attachment you fill in after writing. BMJ Open reviewers and editors can compare the checklist page numbers against the abstract, methods, figures, tables, and supplementary files. If the checklist says an item is on page 7 but the method, sample-size, ethics, or outcome-definition text is missing, the formatter did not solve the submission problem.

The third pitfall is table cleanup. Word tables need editable cells, cited table numbers, column headers, and readable footnotes. A pasted image of a table, a shaded spreadsheet screenshot, or a vertical-line-heavy table can survive a local formatting pass and still create production or review friction.

In our pre-submission review work on BMJ Open submissions, the formatting failures that matter are rarely cosmetic. They usually sit in the manuscript package: abstract headings, reporting checklist upload, ethics statement, PPI statement, data-availability statement, table files, and reference-manager cleanup. Manusights submission analysis treats these as specific failure pattern signals because editors routinely flag the missing file or statement before they evaluate the clinical argument. In practice, we see authors fix fonts and margins while leaving the checklist, ethics, and data-availability evidence misaligned. That is why we check the Word file, supplementary files, and submission answers together instead of treating formatting as a final visual pass.

Reporting checklist not submitted or in the wrong format. BMJ Open requires completed reporting checklists for all study types: CONSORT for randomized trials, STROBE for observational studies, PRISMA for systematic reviews and meta-analyses, STARD for diagnostic accuracy studies, and ARRIVE for animal studies. The checklist must be submitted as a separate file at the time of submission and is verified by editorial staff before the paper is processed. Manuscripts that describe a clinical or observational study without attaching the appropriate checklist are returned for correction.

Ethical approval statement absent or insufficient. BMJ Open requires that all studies involving human participants include a statement of ethical approval specifying the name of the ethics committee, the reference number, and the date of approval. Manuscripts that state "the study was approved by an ethics committee" without specifying the institutional review board name and reference number are returned for clarification. For studies using data from registers or records that are exempt from formal review, a statement explaining the exemption is required.

Patient and Public Involvement (PPI) statement missing. BMJ Open requires all research manuscripts to include a Patient and Public Involvement statement that explains how patients or members of the public were involved in the design, conduct, reporting, or dissemination plans for the research. If patients were not involved, a statement explaining why not is required. Manuscripts that do not address PPI in any form are returned for this addition. This is a BMJ Publishing Group-wide requirement.

Open data statement not included or data not deposited. BMJ Open strongly encourages open data sharing and requires at minimum a data sharing statement that explains what data are available, where they are available, and any conditions under which they can be accessed. If the data cannot be shared (for ethical or legal reasons), this must be explicitly stated with a justification. Manuscripts without any data availability statement are asked to add one before review.

A BMJ Open submission readiness check evaluates manuscript structure, reporting checklist compliance, ethical approval documentation, and PPI statement against these desk-rejection patterns before you submit.

For a manuscript-specific signal before you submit, run a BMJ Open submission readiness check.

Or see example reports before you finalize.