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AMA Style (11th ed): Citing Your Sources

11th edition (2020) AMA style

Reference style or manuscript style?

Being told to write "in AMA Style" can have more than one meaning. Carefully read your assignment or speak with the faculty who assigned it to determine what they want.

Case 1: "Write in AMA Style" is a reference style. This means that the references within the text and the bibliography at the end of the text should follow the guidelines laid out by the AMA Manual of Style. This is frequently used for papers and other writing in classes, and presentations conducted during classes or practice rotations. This guide includes detailed help on creating references in AMA Style.

Case 2: "Write in AMA Style" as a manuscript style. This means using proper references within the text and bibliography, but also using the stylistic matters laid out in the AMA Manual of Style to format the text. This includes such factors as using headings and capitalizing them appropriately, line spacing, margins, text style issues (such as using "one" or "1", using AM or a.m. or A.M.), placement of page numbers, preferred font and spacing for graphs, preferred size and shape for tables, etc. This is more frequently called for when publishing writing, submitting to a journal for peer review, or writing materials for presentation or distribution at professional meetings. This guide includes very little help on manuscript style, as it comprises about 500 pages of the Manual and is difficult to summarize. Consult the AMA Manual of Style for detailed information on manuscript style.

Commonly asked questions about manuscript styling

Acronyms, abbreviations, initialisms:

Acronyms, abbreviations, and initialisms are discouraged from use, except for well-known and accepted units of measurement and some well-recognized terms. 

  • If used, spell out at the first use, even if the acronym or initialism is well-known. Do not place periods between the letters of an acronym, abbreviation or initialism.
  • State names should always appear as full names in the text of a manuscript. If included in references, use the two-letter abbreviation.


Numerals (1, 2, 3, etc.) should be used in all writing, except when:

  • The number begins the sentence or title
  • Common fractions
  • Ordinals: first through ninth
  • Number spelled out in quotations or titles of works cited.
  • One number may be spelled out, if the sentence requires multiple numbers to be placed next to each other. E.g., "If 12 16-year-olds had this reaction..." should be changed to "If twelve 16-year-olds..."


  • To indicate a time of day, use AM or PM in small capitals.
  • Conventional 12-hour clock time is preferred. However, 24 hour or military time convention can also be used to convey precise timing when needed, such as when describing drug dosage regimens.


  • When dates are provided in the text, use numerals for day and year, and write out the month using text. E.g., April 2, 1990.
  • If using dates in a table, you may use numerals for the month (e.g., 4/2/1990).


  • Use SI (Le Système International d'Unitiés) standards for writing measurements. Numbers are always written in plain text, there is a space after the number and prior to the unit, and never a period after the unit (unless it ends a sentence).
  • Do not include commas in longer numbers (e.g. 1600 km, not 1,600 km).

The Web/Internet:

  • Use email. Never capitalize the "e" unless at the beginning of a sentence.
  • Internet and web should not be capitalized.
  • Home page is two words.
  • Web page or web site are two words. Most other compound words starting with "web" are one word and spelled lowercase: webmaster, webcast, webcam, etc.