The two major sets of rules for formatting reports are those of the Modern Language Association and the American Psychological Association. Students use MLA style when writing papers in the disciplines of literature and English; they use APA style more frequently in the social sciences. Both styles have specific rules about how to format Roman numerals and when to use them.
Page Numbering: MLA Style
In MLA style, students number outline pages with Roman numerals. These should be formatted in lowercase. For example, page 2 of an outline would be numbered "ii," not "II." In MLA style, writers place page numbers at the top right of the page. There should be a space of 1/2 inch between the top of the page and the number. Writers should be sure their numbers are flush with the right margin and appear after their last names, with no punctuation between the two. For example, "Smith iii" is correct page numbering in an MLA outline. The first page of an MLA document does not carry a page number.
Page Numbering: APA Style
Students writing in APA style use lowercase Roman numerals for the preliminary pages in a report. They place page numbers centered at the bottom of a page and leave 1 inch of space between the bottom edge of the page and the number. The title page of a report carries no number but counts as the first official page; this means that the certification page carries the page number "ii," the abstract carries the page number "iii," and acknowledgements, if given, carry page number "iv." Students number the table of contents as page number "v" if their report has an acknowledgements page and "iv" otherwise. If the table of contents is more than one page long, subsequent pages of it carry successive Roman numerals. Students writing in APA style switch to Arabic numerals when the main body of their report begins.
Roman Numerals in MLA Outlines
Students also use Roman numerals in the bodies of outlines written in MLA style. In this case, the Roman numerals are formatted in uppercase only. Students use Roman numerals only for the main points of their outlines. They use upper- and lowercase letters, as well as Arabic numerals, for supporting ideas.
It was once common for writers to refer to Bible verses using Roman numerals to distinguish chapter numbers from verse numbers. For example, the 16th verse in the third chapter of John would be referenced as John III:16. Both MLA and APA style discourage the use of Roman numerals in this situation. APA style requires writers to render the reference as John 3:16. MLA style uses a period instead of a colon, rendering the reference as John 3.16.