Preprint Instructions

We aim to make submitting to PeerJ Preprints as easy as possible. At the same time, we want to ensure that Preprints are of the highest quality and integrity and that they adhere to discipline-specific requirements. What follows below are guidelines for meeting both of these objectives.


PeerJ Preprints are not peer-reviewed. They are screened by PeerJ staff to ensure that they fit the subject area; do not contravene any of our policies; and that they can reasonably be considered a part of the academic literature. If a submission is found to be unsuitable in any of these respects then it will not be accepted for posting. Content which is considered to be non-scientific or pseudoscientific will not pass our screening. All decisions of PeerJ staff are final.
PeerJ Preprints publishes these types of content:
  • Research Articles
  • Posters
  • Literature reviews
  • Commentaries
  • Opinion pieces
  • Case studies
  • Case reports
  • ...and others.
PeerJ Preprints publishes in these areas:
  • Biological Sciences.
  • Environmental Sciences.
  • Medical Sciences.
  • Health Sciences.
  • Computer Sciences.
PeerJ Preprints does not publish in these areas (except where there is clear relevance to the Biological, Environmental, Medical, Health or Computer sciences):
  • Physical Sciences.
  • Mathematical Sciences.
  • Social Sciences.
  • Humanities.
  • Work with diagnostic, therapeutic, or health implications or reports on Clinical Trials (these must be peer reviewed for safety).
  • Reports of new taxa, species etc. (these must be peer reviewed).
You cannot publish any materials that have been published in a peer-reviewed journal.
Preprints cannot be unpublished. You can update a preprint by publishing a new linked version.
You can publish in PeerJ Preprints and any of the PeerJ peer-reviewed journals. Other journals may have a different policy however, so please check with them before publishing your preprint.
You can publish a free preprint without publishing in any of the PeerJ peer-reviewed journals.
It is the responsibility of all author(s) to ensure they can publish under our default CC BY copyright license. Note: Some US and UK government employees may be required to publish under a CC0, Public Domain, or OGL license.

Preparing your preprint

Please use clear, unambiguous, technically and grammatically correct English.
Submit as a PDF.
You can structure and style your submission however you wish. But for maximum readability and consistency, please follow the guidelines below.
Manuscript formatting:
  • US Letter.
  • Use line numbers.
  • 2.5 cm margin on all edges.
  • 12 point Times font for readability.
  • 'Normal' style for text, 'Heading' styles for headings.
  • Do not use 'unusual' document styles/templates (e.g. 'Normal (Web)').
  • Left justify all text to the left margin. Do not 'full width' justify.
  • Title guidance:
    • Be clear, appealing, interesting and specific.
    • Match the search queries used to find similar articles.
    • Be concise: ideally 20-60 characters (250 character hard limit).
    • Avoid acronyms, abbreviations and jargon.
    • Accurately describe work.

Suggested preprint formatting guidelines

Standard Sections

Use these Standard Sections where possible. Include any methodology or experiment sections appropriate to your field.
Author Cover Page (see below)
  • 500 word (3,000 character) limit.
  • Self-contained, concise description of reason for the work, methodology, results, and conclusions.
  • Uncommon abbreviations should be spelled out at first use.
  • No footnotes or references (except when referencing a critiqued publication by DOI).
  • Subheadings must be bold, followed by a period, and start a new paragraph e.g.
    Background. The background section text goes here...
Materials & Methods
[methodology / experimental sections appropriate to your work]
  • Do not acknowledge funders here, there is a separate Funding Statement for that. Everyone named in the acknowledgments section must be informed that they are named.

Literature Review standard sections

Author Cover Page (see above)
Abstract (see above)
  • Describe the field and explain why this review is needed.
  • Explain relevance to readers in the field, and associated areas.
  • Cite previous reviews.
Survey Methodology
  • Explain how you ensured comprehensive and unbiased coverage of the literature.
  • We recommend that you subdivide your article into a small number of major topic areas.
  • Identify unresolved questions / gaps / future directions.
Acknowledgments (see above)

Author cover page

Included as the first page of your manuscript (view example).
Author info entered online must match the author info in your Author Cover Page.
Author Cover Page structure:
  • Article title
  • Authors
    • First names (or first initials in combination with full middle names).
    • Middle name initial(s).
    • Last names (surname, family name).
  • Affiliations (indicate multiple affiliations, or current addresses where appropriate).
    • Department, university, or organizational affiliation.
    • Location: city, state/province (if applicable).
    • Country.
  • Corresponding Author
    • First and Last name.
    • Email address.


  • If authored by a consortium, list names and affiliations in correct order in the Acknowledgments section.
All authors must meet the ICMJE authorship authorship requirements. Include other contributors in the Acknowledgments section.

Reference Format

Choose your style

PeerJ prefers you spend your time doing science, not formatting references!

Submit your references in whatever style you like.

Just make sure they're full, clear, and consistent.

PeerJ uses the 'Name. Year' style with an alphabetized reference list.
In-text citations
  • For three or fewer authors, list all author names (e.g. Smith, Jones & Johnson, 2004). For four or more, abbreviate with ‘first author’ et al. (e.g. Smith et al., 2005).
  • Multiple references to the same item should be separated with a semicolon (;) and ordered chronologically.
  • References by the same author in the same year should be differentiated by letters (Smith, 2001a; Smith, 2001b).
  • Cite articles accepted for publication as 'in press'. Include in reference section and upload as a Supplemental file.
  • Cite work unpublished, in preparation or under review as 'unpublished data'. Use the author's initials and surname in the text only. Do not include in the reference section.
  • Avoid referencing personal communications. Reference as 'pers. comm.', including the name and year.
The Reference Section
  • Journal reference format: List of authors (with initials). Publication year. Full article title. Full title of the Journal, volume: page extents. DOI (if available).

    Example journal reference:
    Smith JL, Jones P, Wang X. 2004. Investigating ecological destruction in the Amazon. Journal of the Amazon Rainforest 112:368-374 DOI: 10.1234/amazon.15886.

  • Gray Literature (e.g. patents, technical reports from agencies or research groups, working papers, white papers, preprints etc.) described thoroughly: Authors. Page/paper title. Publication date. Publisher name. URL (access date). Identification (e.g. patent or series) numbers.

    Example gray literature references:
    Boettiger C. 2013. knitcitations: citations for knitr markdown files. Available at (accessed 10 July 2012)
    Dorch B. 2012. On the Citation Advantage of linking to data. hprints. Available at (accessed 5 July 2012)

  • Example book reference:
    James FY. 2010. Understanding corn and wheat. Oxford: Oxford University Press.

  • Example book excerpt:
    Smith PG. 2011. Behavior in ants. In: Jones HY, ed. Insect behavior in the Andes. Berlin: Springer Verlag, 101–200.

  • Example thesis:
    Blair HJ. 1989. Structural modifications of the fern genus Lecanopteris (Polypodiaceae). D. Phil. Thesis, Cambridge University.

  • Example webpage:
    Johnson S. 2010. Italian Plants. Available at (accessed 22 March 2011).

  • Example abstract:
    Thomas D, Scharfenecker U, Schiltmeyer B. 2006. Low potential for drug-drug interaction of lacosamide. [Abstract 2.235] Epilepsia 47(Suppl 4): 200.

  • Reference Section sorted by Author, Year, Title. All citations must be present in the reference section, and all references cited in the text. Place non-cited references in a "Further Reading" section.
  • Zotero users please download PeerJ Zotero style.
  • EndNote users please download PeerJ Endnote style and:
    • Open EndNote.
    • Open library (the citation file).
    • Set style to "PeerJ".
    • Go to Edit --> Output Styles --> Edit "PeerJ".
    • Under Bibliography --> Author Lists, set "Abbreviated author list" to "List all author names".
  • Mendeley users in MS Word please change your field codes into plain text by performing the following:
    • If using Windows:
      Ctrl-A (Selects all the text in the manuscript).
      Ctrl-Shift-F9 (Changes the fields codes).
    • If using OSX:
      Command-A (Selects all the text in the manuscript).
      Command-6 (Changes the fields codes).

File Types

Your preprint is submitted as a single PDF.

You can choose to upload additional figures, tables and other supplemental files as part of your publication.

  • 'Figure' refers to graphs, charts, line drawings and photographs.
  • Minimum white space around each figure/figure part.
  • Label with a readable, uniform font. Vertical height of 2mm suggested.
  • Multi-part figures submitted in one file and arranged as they are to be published. Label each part with an uppercase letter.
  • When citing use the abbreviation 'Fig.'. When starting a sentence with a citation, use 'Figure 1'.
  • Aim to use the dpi resolution noted below. Ideally, reproduction of the image at 100% will result in image sizes no larger than 17 cm (6.7 in) wide and 23 cm (9.2 in) high:
    • - 300 dpi for grayscale and color.
    • - 600 dpi for combination art (lettering and images).
    • - 1,200 dpi for line art.
  • Table document formats:
    • .DOCX (Preferred) and .DOC
    • .ODT
    • .PDF
    • Include table numbers in filenames e.g. 'Table 1.png'.
    • Cite tables in text as 'Table 1', 'Table 2' etc.
    • Include units in column and row headings, in parentheses.
    • Tables must fit in a single 21.6 x 28 cm page with 2.5 cm margins.
    • Place footnotes below the table; these may be used to explain abbreviations.

      Figure and table referencing

    • For figures, videos or tables containing copyrighted material not created by one of the authors (e.g. photographs, maps):

    • When submitting photographs please indicate the identity of the photographer.

    • Examples of credit attributions:

      Photo credit: San Diego Zoo Global.
      Photo credit: Ali Smith.
      Image credit: the MESH archive at
      3D model credit: Ishmael Kreill
      Map data © 2018 Google

    • For figures with identifiable human subjects:
      • Written consent from the human subject. If the subject is a minor, consent must be provided from their parent or guardian.
      • Upload a document with the copyright owner's permission to publish under a CC BY licence
        (download photo/video permission letter template).
    • Cite map sources. If using Google Earth or Google Maps also attribute the third-party data providers used by the map:
      • In the figure legend.
      • On the figure.
    • Use maps which allow unrestricted re-use where possible.

    TeX / LaTeX users
    Upload your complete PDF, and optionally upload source files in the Supplemental files section.

    Raw data or code
    • All authors are responsible for making materials, code, raw data and associated protocols relevant to the submission available without delay.
    • Data or code should be submitted to a specialist database if appropriate (e.g. GenBank for sequences, Morphosource for 3D models and scans, etc.).
    • Recommended data or code repositories:

    Supplemental Information (SI)

    Supplemental Figures Submit as JPG (use maximum quality settings), EPS (for vector images), or PNG (for lossless images).
    Supplemental Tables Submit as PDF, DOC, Excel, RTF or TeX / LaTeX files.
    Supplemental Articles Submit as PDF.
    Supplemental Videos Submit as AVI, MOV, and MP4 files. For widest compatibility, we suggest authors provide video files as 128 kbit/s AAC audio and 480p H.264 video in an MPEG-4 (mp4) format. Regardless of format submitted, authors should double check that their videos open and play in recent versions of both QuickTime and Windows Media Player.
    Supplemental Audio Submit as WAV or MP3 files. Please include a legend. Ensure that the files open and play in common audio players such as iTunes or Windows Media Player.
    Large Supplemental Data sets Submit in a compressed format (e.g. zip or tar.gz).
    • Supplemental files are published alongside your Preprint.
    • Supplemental files may include information or data too large to include in the main article.
    • File naming format: 'Supplemental [Item] S[number]' e.g. 'Supplemental Data S1'.
    • Titles are required for all figures (legends are optional).
    • Supplemental Files should not exceed 50 MB in total (30MB individual file limit). If you need more space please contact us.
    • Use the following style when citing Supplemental files in the text:
      Fig. S1, Table S1, Data S1, Video S1, Article S1, Audio S1.

    Style Considerations

    Units, Symbols, Mathematics, Abbreviations
    • Where possible and appropriate, use the International System of Units.
    • Use discipline specific (non-SI) units only where they are widely adopted within the field.
    • Symbols should be used in lieu of abbreviations for mathematical expressions & defined at first use.
    • Spell out the numbers 1-9 unless used with units.
    Manuscript Text
    • Please use clear, unambiguous, technically and grammatically correct English.
    • The established norms of academic writing within your field should be followed.
    • Either English or American spelling is acceptable provided it is consistently used throughout.
    • Nomenclature: Biological & medical nomenclature should adhere to recognized guidelines set forth by international committee regulations or authoritative bodies for specific fields, as applicable.
    • Formal results should include clear definitions of all terms and theorems, and detailed proofs.
    • Table text should be roman black text.
    • Special significance can be placed on certain values in the table (e.g., p-values) by bolding, italicizing or underlining the text. Explain in the table legend what the formatting represents.
    • Image manipulation:
      • Figures should be minimally processed/manipulated, to add labels, arrows, or change contrast (applied to whole image inc. controls).
      • Do not adjust in any way that could lead to misinterpretation of the information in the original image.
      • Descriptions of changes and hardware and software used to take the images and make adjustments must also be provided.
      • Inappropriate figure manipulation is grounds for article retraction and reporting to institutional oversight boards.
    • Electrophoretic gels and blots: Use cropped gels and blots in your article only if it improves clarity. Upload full-length gels and blots as Supplementary Files if doing so.
    • Include scales, abbreviations, limits etc. in the graphical area the image.
    • Figure legends should be self contained and clearly describe the figure and its contents.
    • When creating figures and images consider the accessibility of your chosen color schemes to those with non-normal color vision. Wherever possible avoid using color alone to distinguish between parts of images. When color is used, we suggest that you consult the following resources to ensure maximum accessibility: J*FLY, Mapbox and ColorBrewer.
    Linnean Binomials
    • Authors are encouraged to provide taxonomic authors of Linnean binomials when first used in the text, particularly for taxa that are the focus of the paper in question. Where several taxa are named, citation of taxonomic authors in Tables is regarded as an adequate substitute for citation in the body of the text. Authors of zoological names should consist of initials plus full surnames, whereas authors of botanical names should be abbreviated following Brummitt & Powell's (1992) 'Authors of plant names'. In either case, binomials carrying more than three authors should be abbreviated to 'et al.' subsequent to the name of the third author.
    Species formatting
    • When a species is first mentioned, write out the full name (i.e., genus followed by species):
      • Use both the genus and species name (e.g., Felis catus).
      • Italicize the whole name.
      • Capitalize only the genus name.
    • The next time that species is mentioned, abbreviate the name (i.e., the first letter of the genus followed by a period and the species), unless:
      • There are two species that belong to different genera that nevertheless start with the same letter (e.g., Leopardus pardalis, the ocelot, and Lynx canadensis, the Canada lynx). Do not abbreviate the genus name.
      • There are multiple species with the same species name, but different genera (e.g., Trigonopterus attenboroughi, a beetle, and Prethopalpus attenboroughi, a spider). You can refer to the species by just the genus name, or write the species name in full.
      • There are two or more species that are are being compared in the same sentence. In this case, you can refer to the species by just the genus name, or write the species name in full.
    • When you introduce the name of another species in the same genus, you can use the abbreviated genus name for the new species. For example: The domestic cat is species Felis catus. Both F. catus and its wild relative, F. silvestris...
    • The names of higher taxonomic levels (family, order, class, phylum or division, and kingdom) should be capitalized but not italicized. Common names derived from taxon names, for instance “felines” for members of the family Felidae, should not be capitalized. A common name that is derived from a genus name, such as gorilla, should not be capitalized.