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.

Scope & Instructions

PeerJ Preprints is a 'preprint server' for the Biological Sciences, Environmental Sciences, Medical Sciences, Health Sciences and Computer Sciences.
PeerJ Preprints accepts Research Articles, "Posters", Literature Review Articles, Commentaries, Opinion Pieces, Case Studies, Case Reports, etc.
PeerJ Preprints does not publish in the Physical Sciences, the Mathematical Sciences, the Social Sciences, or the Humanities (except where articles in those areas have clear applicability to the core areas of Biological, Environmental, Medical, Health or Computer sciences).
Submissions to PeerJ Preprints are not formally peer-reviewed. Instead 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.
Because PeerJ Preprints is not peer-reviewed, and mindful of the risks to human health of inaccurate information, PeerJ Preprints does not accept submissions which have diagnostic, therapeutic, or health implications or report on Clinical Trials.
PeerJ Preprints does not publish reports of new taxa. Reports of new species, etc. must be peer reviewed before publication.
In order to maintain the integrity of the scientific literature, authors should not post material which has been previously published in, or which has been accepted for publication by, a formal peer-reviewed journal.
At present, PeerJ Preprints only accepts PDF uploads for the main document (in addition to Supplemental Files). Future developments will expand on this.
PeerJ Preprints forms a permanent, citable archive and as such submissions cannot be removed once posted. Versioning is available, allowing authors to iteratively improve their drafts.
Submission to PeerJ Preprints does not prevent evaluation, or publication, in the PeerJ journal. However other publishers may have different policies in this respect, so authors should make their own enquiries if they wish to submit a PeerJ Preprint to another journal.
Submission to PeerJ (the peer reviewed journal) is not a requirement for a preprint submission.
All content in PeerJ Preprints is published under a CC BY license. It is the responsibility of the author(s) to ensure that they have the rights to post under this license.

Preparing your preprint

Currently, Preprints are only accepted as a PDF upload. Word, LaTeX, or OpenOffice users must generate a PDF.
Although not a requirement, we recommend that Preprints include line numbers, an approx. 2.5cm margin on all edges and 12 point Times font for readability. This can greatly help readers refer to specific sections when providing feedback.
Use of style documents (for example by LaTeX users) are encouraged in order to present a consistent styling.
We recommend (but do not require) that you format your submission using the guidelines below. Doing so will improve readability and consistency.

Suggested preprint formatting guidelines

Basic Manuscript Organization

The Author Cover Page listing all authors and affiliations must be the first page of the manuscript document you submit (view example). To include:
  • Article title
    • The title of the manuscript should employ "sentence case." For example, "Only the first word is capitalized, except for proper nouns, like San Francisco."
  • Authors
    • First names (or first initials in combination with full middle names)
    • Middle names (or initials, if used)
    • 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 the article was authored by a consortium, list full names and full affiliations in the intended order for publication in the acknowledgements.
A standard front page is added to your reviewing manuscript when it is generated by the system. Please make sure that the author order and details on this standard front page (entered by you in our online submission forms) exactly match that in your Author Cover Page described above.
Contributors who do not qualify under ICMJE authorship guidelines should not be listed as authors. They should be included in the Acknowledgements and should agree to being acknowledged.

Standard Sections

PeerJ Preprints covers a wide range of fields and although we can accommodate a variety of ‘standard sections’, we recommend that the following Standard Sections, in this order, are used wherever possible. Note: Short preprints may not require all sub-sections.
Author Cover Page (see above)
  • No more than approx. 500 words (or 3,000 characters).
  • The abstract must be self-contained and concisely describe the reason for the work, methodology, results, and conclusions. Uncommon abbreviations should be spelled out at first use. Do not include footnotes or references except where the submission is a critique of a specific published work, in which case there must be enough information in the abstract to allow the reader to find it - ideally, a Digital Object Identifier (DOI).
  • Headings in structured abstracts should be bold and followed by a period. Each heading should begin a new paragraph. For example:
    Background. The background section text goes here. Next line for new section.
    Methods. The methods section text goes here.
    Results. The results section text goes here.
    Discussion. The discussion section text goes here.
Materials & Methods
  • As a matter of courtesy, we suggest you inform anyone whom you acknowledge.

For Literature Review Articles we recommend the following Standard Sections:
Author Cover Page (see above)
Abstract (see above)
  • Describe the field being reviewed; note the reason(s) for needing this review; and detail the relevance to readers of PeerJ in both the immediate field and and any associated areas.
  • Cite any previous reviews of the field.
Survey Methodology
  • Describe the process by which you ensured that your coverage of the literature was comprehensive and unbiased.
  • We recommend that you subdivide your article into a small number of major topic areas.
  • Identify unresolved questions / gaps / future directions.
Acknowledgements (see above)

Reference Format

Formatting Tip

We want authors spending their time doing science, not formatting.

We include reference formatting as a guide to make it easier for editors, reviewers, and preprint readers, but will not strictly enforce the specific formatting rules as long as the full citation is clear.

There are no specific styling requirements for Preprints. However, the peer reviewed journals use the "Name. Year" style with an alphabetized reference list. The below is a suggestion only for Preprints.
In-text citations
  • For three or fewer authors, list all author names (e.g. Smith, Jones & Johnson, 2004). For four or more authors, 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 that have been accepted for publication as 'in press', include in the reference list, and provide a copy in the Supplemental Information.
  • Cite unpublished work, work in preparation, or work under review as 'unpublished data' using the author's initials and surname in the text only; do not include in the reference section
The Reference Section
  • Each journal reference should be listed using this format: the full list of Authors with initials. Publication year. Full title of the article. Full title of the Journal, volume: page extents. DOI (when it's 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.

  • References to 'gray literature' such as patents, technical reports from government agencies or scientific research groups, working papers from research groups or committees, white papers, and preprints should be described as thoroughly as possible. Include any author names, titles of the page or the paper, publication date, names of publisher where possible, URL, accessed by dates, and identification numbers such as patent numbers, series numbers as applicable.

    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.

  • References to personal communications should be avoided, but, if absolutely necessary should be referred to as "pers. comm." followed by the relevant year.
  • The References Section should be sorted by Author, Year, Title.
  • EndNote users can download a PeerJ style.

File Types - Preprints

Because your preprint is uploaded as a 'complete PDF' (with all information already included), you do not need to supply separate files. However, if you wish then you can make any files available for others to download. If you choose to do this, then the below represent suggested guidelines for file formats.

  • For clarity, when creating your figures, name the files with the figure number (e.g. include "Figure 1" or "Figure 2" as part of the filename).
  • Unnecessary white space should be eliminated around each figure & figure part.
  • Uniform fonts and font sizes should be used for labels (letter sizing should be readable at ‘actual sized’ reproduction - we suggest a vertical height of 2 mm); multi-part figures should be labeled with a single number for the whole figure group and an uppercase letter for each figure part (e.g. Fig. 3C).
  • 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.
… can be submitted as .DOC (MS Word), .DOCX (MS Word), .ODT (Open Doc), or PDF.
  • For clarity, the name of your uploaded files should include "Table 1" "Table 2" etc.
  • Cite tables in text as "Table 1." "Table 2."
  • 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.
  • Note that our system allows multiple files to be uploaded at once.
TeX / LaTeX users
... since our system does not currently convert .tex files, we ask that you upload a PDF that you have generated yourself as the preprint. Then upload the source tex files as a "Supplemental file" if you would like others to have access to the original source.
Data and Materials
  • All authors are responsible for making materials, code, raw data and associated protocols relevant to the submission available without delay.
  • Please ensure that all relevant datasets, images and information are available in one of the following possible ways and provide a link to the appropriate location: uploaded as Supplemental Files, deposited in a public repository, or hosted in a publicly accessible database.
General Formatting
... Any preprint files are published as links alongside your preprint PDF, which point to downloadable files. As they are provided as ‘original’ files, readers will need to be able to open them using their own resources. Therefore to ensure widest compatibility you should utilize common file types and avoid proprietary formats.
  • In total, all preprint files should not exceed 50 MB (if more space is needed, please contact us). Individual files should not exceed 30 MB.
  • Note that our system allows multiple files to be uploaded at once.
  • If it's necessary to cite preprint files in the text, use the following style: Fig. S1, Table S1, Data S1, Video S1, Article S1, Audio S1.

For maximum compatibility, we suggest that you submit Supplemental Information using the following formats:
Preprint Figures Submit as JPG (use maximum quality settings), EPS (for vector images), or PNG (for lossless images).
Preprint Tables Submit as PDF, DOC, Excel, RTF or TeX / LaTeX files.
Preprint 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.
Preprint 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 Preprint Data sets Submit in a compressed format (e.g. zip or tar.gz).

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.
Preprint Text
  • Preprints must be written in clear, unambiguous English for an international audience.
  • 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.
  • 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 only be (minimally) processed or manipulated in order to add labels, arrows, or to change contrast or brightness if applied to the entire image as well as the controls. They should not be adjusted in any way that could lead to misinterpretation of the information in the original image. Unprocessed figure files and data must be retained for editorial review upon request. The descriptions of changes, hardware and software used to take images and make adjustments must also be provided. Inappropriate figure manipulation is grounds for article retraction and/or reporting to institutional oversight boards.
  • Electrophoretic gels and blots: The display of cropped gels and blots in the preprint is acceptable if it improves its clarity. In such cases, full-length gels and blots should be added to the supplementary file section on submission.
  • "Figure" refers to all images such as graphs, charts, line drawings and photographs. When citing figures in the text, the abbreviation "Fig." should be used. If the citation is the beginning of the sentence, use the full word "Figure" instead.
  • All figures should be referenced within the text.
  • Figure legends should be self contained and clearly describe the figure and its contents.
  • The graphical area of a figure should include information about scales, abbreviations, limits, etc.
  • When submitting photographs as figures please indicate the identity of the photographer. If the photographer is not one of the co-authors, please upload a supplemental document with permission from the photographer allowing you to publish the image under a CC BY license.
  • If you use a map as a figure please cite the source of the map. Wherever possible, use map services which allow unrestricted re-use. If you must use Google Earth or Google Maps then in order to accurately attribute a map from Google, we need to know the third-party data providers cited with the map (find out how here).
  • 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.