How do I write a cover letter for a journal submission?

Cover letters get read, briefly, by someone deciding whether to spend reviewer time on your paper. That is the whole audience and the whole purpose, and it explains what belongs in the letter and what does not.

The first paragraph should contain your finding, stated as a result rather than as an activity. "We show that informal mentoring predicts three-year retention independently of formal programmes, in a national sample of 4,200 teachers" does the job. "We examine the relationship between mentoring and retention" does not, because it tells the editor nothing they could not get from the title.

The second paragraph is about fit, and it should name something specific: a recent paper in the journal your work extends, a debate the journal has hosted, a readership that would use the finding. Generic flattery about the journal's standing is skipped by every editor who reads it.

Published guidance for biomedical authors converges on four things the letter has to carry: novelty, importance, the take-home message, and fit with the target journal (Bahadoran et al., 2021, p. 1). The same guidance sets a firm length, one page and under 200 words, with importance, novelty, implications, and the take-home message compressed into the central paragraph (Bahadoran et al., 2021, p. 2). It also records a dissent worth knowing about. Some authors and editors treat the cover letter as redundant because it repeats the abstract and the online submission fields, and an inaccurate letter turns into a misleading commercial advertisement (Bahadoran et al., 2021, p. 5). Accuracy is what keeps the letter worth reading.

The header does more work than it looks like. Name the journal, give the submission date, and state the manuscript title, type, author list, and length, plus whether the submission follows an invitation or belongs to a special issue (Bahadoran et al., 2021, p. 2). Where a journal has several co-editors, address the one whose background matches your topic, and when responsibility is unclear, write "Dear Editors" rather than the vaguer "Dear Editor" (Bahadoran et al., 2021, p. 4).

The third paragraph carries the declarations: that the work is original, not under consideration elsewhere, that all authors approved the submission, plus ethics approval, funding, competing interests, and any AI disclosure the journal requires. Check the instructions for authors, since several journals now ask for the AI statement in the cover letter specifically.

What does an editor actually read it for?

Two things. Whether the paper belongs in their journal, and whether the authors understand what they have. A letter that describes the topic without stating the finding suggests the paper may do the same, which is a reason to look at the abstract more sceptically.

Editors also look for anything that would stop the submission proceeding: a missing ethics statement, an undeclared overlap with a previous publication, or a conflict of interest. Handling these upfront prevents a delay later.

Rejection data shows how early those judgments happen. A content analysis of 898 rejection reports at the Indian Journal of Psychological Medicine, covering January 2018 to May 2020, found that 627 of them, 69.8%, were desk rejections, with a median desk-rejection time of three days (Menon et al., 2022, p. 59). Rejection rates ranged from 26.7% for viewpoint articles to 72.1% for reviews, and the two most common desk-rejection reasons were lack of novelty and falling outside the journal's scope (Menon et al., 2022, p. 61). That is one journal in one field, not a general rate, and no cover letter rescues a paper an editor considers unoriginal. Both reasons, though, are ones your fit paragraph can speak to before the editor forms the judgment on their own.

Keep it to one page. A three-page cover letter signals that the paper does not speak for itself.

Should I suggest reviewers?

Yes if the journal asks, naming people who work on the problem but have no conflict with you, and never a co-author, supervisor, or colleague from your institution. You may also request exclusions, briefly and without explanation. Editors are not obliged to follow either list.

Suggest people whose work you engaged with substantively, including anyone whose position you argue against. Suggesting only friendly reviewers is transparent, and suggesting a critic signals confidence.

Give full names, institutional email addresses, and one line on why each is qualified. Editors are more likely to use a suggestion they can act on without further searching.

Guidance for authors draws the conflict boundary concretely. Suggest reviewers only when the journal requests them, and do not name friends, colleagues, or anyone you have published with in the previous five years (Bahadoran et al., 2021, p. 4). The same source rules out padding elsewhere in the letter, including jargon, acronyms, unrelated personal information, and inflated accounts of your previous publications or academic honours.

Exclusion requests are legitimate where a genuine conflict exists, such as a direct competitor or someone with whom you have a documented dispute. Keep the list to one or two names, since a long exclusion list makes an editor wonder how many people you have fallen out with.