How to Write an Index

Five Parts:Reading to IndexFormatting the HeadingsFormatting SubentriesEditing the IndexPreparing to Create a Professional Index

An index, while never the most glamorous section of any writing project, is essential to the readability and usability of longer nonfiction pieces, technical articles, and books. It is an alphabetical listing of keywords and concepts in the text. It contains "pointers" to those words and concepts, which are usually page, section, or paragraph numbers.[1] It generally appears at the end of a work. Building one need not be a chore, but it should not be an afterthought, either. It’s important to make an index that is useful and comprehensive for your readers, but doesn’t occupy too much of your valuable research and writing time. If you think it might, don’t worry; you can hire a professional index writer.

Part 1
Reading to Index

  1. 1
    Identify what needs to be indexed. There are several elements that must be indexed in any text, including:[2]
    • The entire text of the book, including the introduction and any content notes
    • If the footnotes and/or endnotes continue or expand on the text, they should be indexed. However, if the footnotes and/or endnotes are source citations, they should not be indexed.
    • Depending on the field, you may need to index every author named in the text. Check with the publisher about this requirement. It may appear as a separate author index, or be included in your general index.[3]
  2. 2
    Recognize what not to index. A good index is selective, not exhaustive. Don't index things that are not central or important concepts or keywords.[4]
    • Avoid indexing minor mentions. For example, if a famous person's name has been mentioned in a quote but is not discussed anywhere else in the text, this person's name is not index-worthy. Ask yourself: is there something substantial to read about the word or concept within the text? If the answer is no, it does not need to be indexed.
    • Do not include title pages, dedications, epigraphs, lists of illustrations and tables, and acknowledgements in the index.
    • Do not include glossaries or bibliographies in the index.
    • Do not index names of people, places, things, or concepts that are only used as examples or brief mentions.
    • In general, do not index illustrative items like tables, charts, pictures, etc.
  3. Image titled My Pile of Index Card
    Identify what will become your entries. The entries in an index are the major concepts and keywords that a reader is likely to search for in the text. Entries consist of headings (or main headings), subentries, cross-references, and locators.[5]
    • For example, a full entry in an index might look like this: ice cream, varieties of: lemon, 54; Neapolitan, 55; strawberry, 56. See also sorbet.
    • ”Ice cream” is the heading, as it is the overall concept that readers will want to locate. The elements after the colon are the subentries, or varieties of the main heading (in this case, specific types of ice cream). The “see also” element is a cross-reference, as it suggests to readers that additional, similar information can be found in another entry.[6] The locators are the page numbers.
    • The type of headings your index includes will depend on how specific your text is.[7] For example, a book on bicycle maintenance would likely not use “bicycle” as a header, because it would generate a huge list of results. However, good headers for this book could be a parts of a bike you may need to fix, such as gears, bike wheels, or bike chain. Terms that relate to these key terms, such as spoke key, tire pressure, or lubricant, could also be helpful.
    • A book on methods of transportation could use “bicycle” as a header, since it is a major type of transportation, and so readers are likely to want to locate it.
    • A biography's index will always include an entry headed with the name of the person who is its subject, often the longest entry with many sub-headings. People who have been known by more than one name may also have separate pointers to the main entry, for instance "Blair, Eric Arthur, see George Orwell".
    • Keep in mind a long list of terms can actually cause duplicates and confusion, as well as hinder your ability to structure and compile an index. So if possible, ask the author to limit the list of terms to only essential ones.
  4. 4
    Review the entire text and mark any keywords or main topics. Pay particular attention to the section headings, the introductions, conclusions and the overall structure of the text.[8]
    • Aim for about two to three index inclusions per key point and main idea, minimum.
    • If you are using a word processing program that has indexing features, begin tagging any topics or key terms are you read.[9]
    • You can also sticky notes, index cards, or any type of written shorthand that will help you find terms and topics easily. Look at the text chapter by chapter, section by section, to ensure you have identified all the possible key terms and topics.
    • While copyediting is not the main purpose of building an index, you will be doing a thorough reading of the text so you may wish to use the opportunity to catch and correct any lingering errors you may have missed.

Part 2
Formatting the Headings

  1. 1
    Organize the main headings in alphabetical order. If you are using a word processor, the program may be able to perform this step automatically for you.[10]
    • Don’t rely on the indexing capacity of your word processing software to create an index. It will actually create a concordance, which will list all of the words in your text and their page numbers. This is much less helpful than a true index, which is focused to only those topics and keywords that a reader is likely to search for.[11]
  2. 2
    Use nouns, rather than adjectives or verbs, for your index headings.[12] Nouns referring to people, places, objects, or concepts, are the most common type of index header.[13] Singular nouns are appropriate in most cases.
    • For example, a cookbook might have “ice cream” as a heading, but not “lemon ice cream” or “Neapolitan ice cream.” Those would be subentries.
    • For proper nouns, such as the “American Revolution,” use all words in the proper noun as the heading. Capitalize proper nouns, but leave everything else lower-case.
    • List all proper nouns separately: for example, “United States Senate” and “United States House of Representatives” would not be subentries under “United States.”[14]
    • You may also use a noun phrase, although you should usually invert it to put the term that the reader is searching for first. For example, “adjusting-height saddle” would be inverted to “saddle, adjusting-height.”[15]
  3. 3
    Create cross references for acronyms and initial-isms. If your keywords will include acronyms, list the acronym and include a cross-reference to the full term.
    • For example: MTB, see mountain bike
  4. 4
    Do not attempt to say too much. Good headers are clear and concise. Perhaps your book about comic books discusses Wonder Woman’s influence on the feminist movement of the 20th century. “Wonder Woman’s influence on the feminist movement of the 20th century” would not be a good header: it is long and unwieldy. You have a couple of options in this situation:[16]
    • Put this as a subentry under the header “Wonder Woman,” like so: Wonder Woman: and feminism, 24-48.
    • Put this as a subentry under the header “Feminism,” like so: Feminism: and illustrators, 45-50; influence of Wonder Woman, 24-48.
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    Review your headings to make sure they work with the needs of the reader. It’s important to remember you are creating an index that will make it easier for the reader to search for key terms or topics they will intuitively want to look for.[17]
    • Look over the headings and consider if there are any key terms or topics that may be confusing for the reader and simplify or adjust any of the headings.
    • For example, a bicycle maintenance text might discuss derailleurs, but a reader who is new to bicycle maintenance may not know this term and look for more common terms like "gearshift" or "shifter."

Part 3
Formatting Subentries

  1. 1
    Identify subentries. Once you have your headers, you will need to figure out whether those keywords or concepts need to be broken down into subentries. In some cases, such as a single recipe in a cookbook, you won’t need subentries. In many cases, you will need them. Subentries should be as concise and informative as possible.[18]
    • The most common reason to use subentries is to form subdivisions within big categories.[19] For example, if you have a cookbook to index, you might have “soups, cold” and “soups, hot” as headers, and specific recipes as subentries within those headers. Place a colon after the header, and then list the subentries in alphabetical order (excluding conjunctions), with their locators. For example:
    • soups, hot:
      • beef stew, 17; chicken noodle, 12; mulligatawny, 15; split pea, 13.
  2. 2
    Use subentries if the same header has more than 5 or 6 locators (e.g., page numbers). For example, if you were writing a political science textbook, “capitalism” is likely a header that readers will search for. It probably also has a variety of mentions with different contexts, so offering subentries that are more specific will help your readers locate the mention most relevant to their needs.[20]
    • Place a colon after the header, and then list the subentries in alphabetical order (excluding conjunctions), with their locators.
    • For example: capitalism: 21st century,164; American free trade, 112; backlash against, 654; expansion of, 42; Russia, 7; and television, 3; treaties, 87.
    • You can use both kinds of subentries in the same index.[21]
  3. 3
    Punctuate properly. Separate subentries from the header with a colon (ice cream: lemon, 54). Separate subentries from each other with semicolons (ice cream: lemon, 54; Neapolitan, 55; strawberry, 56). Use a comma between each subentry and its locator (lemon, 54).[22]
  4. 4
    Do not include prepositions like ‘a’ ‘an’ and ‘the’ in the subentries. As well, as a general rule, use ‘and’ sparingly at the beginning of a subentry as it will reduce the reader’s ability to quickly scan the index for a term or topic.[23]
    • You can usually ignore any symbols, hyphens, slashes or numbers in the subentry terms.
    • Do not repeat main terms in subentries If several subentries contain the same key word, they can be added in a separate header under the keyword, with a cross-reference back to the original header.
    • If you are using a word processor with indexing software, the subentries can be set to recognize three classes of characters: letters, Arabic numerals, and symbols.[24]
  5. 5
    List the page numbers on which each subject appears. Publisher guidelines vary, but in general, you can use the Chicago Manual of Style as a guide to locators.[25][26]
    • If the first locator number is 1-99, use all the digits for the second locator: 3-10, 99-104
    • If the first locator number is 100 or multiples of 100, use all the digits for the second locator: 100-109, 200-255
    • If the first locator number is 101-109 (or multiples), use only the changed numbers: 401-9
    • If the first locator number is 110-199 (or multiples), use the changed numbers as necessary: 223-58, 112-18
    • You can use the word passim to indicate that references are scattered over a range of pages: capitalism, 45-68 passim. This is best reserved only for when there are a large number of references in a section.[27]
    • If you have access to a PDF version of the text, use the PDF search feature to ensure you have located every occurrence of a term and have the correct page numbers for each term.
  6. 6
    Add synonyms for the key terms. Consider your audience and the terms they will be more familiar with, especially if you are indexing a beginners manual or guide to a topic.[28]
    • For example, a beginner cyclist may refer to patches on their tires as “tire patches”, when in fact in cycling terms, a tire patch is actually called a “boot”. So it may be important to include both terms so it is easy for a beginner cyclist to look up this information.[29]
  7. 7
    Add cross-references. Cross-references will direct the reader to topics that relate to a specific topic, or offer additional information.[30] “See” cross-references tell the reader to look for a different header, such as “Cycle. See Bicycle”. “See also” cross-references offer additional or related information.
    • Use the subentries to create “See also” cross-references. Italicize both words, and capitalize “See”.
    • Separate multiple cross-references with semicolons (See also saddle; kickstand).[31]
    • Ensure the cross-references match the exact wording of the headings.
    • For example: “Bicycle: maintenance, 4; purchasing, 8; saddles, 22; tires, 16. See also Tricycle”

Part 4
Editing the Index

  1. 1
    Review the index for cohesion and accuracy. Check all headings and subentries to ensure they highlight the key terms and topics in the text.
    • Go through the text and check it against the index to ensure all major topics and concepts have been covered.
    • If you used a word processor to create the index, double check that the program hasn't indexed an entire sentence from a section header that has no helpful referencing point. For example, a header might be called "Repairing bicycles isn't easy" and the computer index might add the whole phrase. This doesn't tell the reader anything helpful in terms of specificity of words or concepts, so it needs to be broken down into heading and subentry.
  2. 2
    Proofread the index. Review the index line by line for any spelling or grammar mistakes.[32] Do not include final punctuation on any line of the index.[33]
    • The spelling in the index should always reflect the spelling found in the author’s text.
    • Proofing a hardcopy of the index is usually more effective than doing it on a computer screen.
    • If you are using indexing software, it will have a spell check that can be customized, but checking the hard copy version is also a good idea to ensure you have caught any errors.
    • Ensure all page number or locators are correct. Carry out a spot check of each page entry to make sure they match correctly.
  3. 3
    Format the index. Once the index has been edited and proofread, it should be formatted to the dimensions required by the publisher.
    • In printed works, the indexes are usually set with a smaller font than the main text. So if the main text is twelve point, the index will likely be set at eight or ten point.
    • The index is usually set in two columns. For large format books, the indexes may be set in three or four columns.
    • Make sure the index entries are indented properly and consistent throughout.
    • If possible, have someone try out the index who is unfamiliar with the work.
  4. 4
    Trim the index down, if needed. If the index seems too long or you are told by a publisher that is it too long, edit or rephrase headings and subentries to shorten them.
    • Keep in mind minor or trivial entries can often be deleted, as well as some cross-references and acronyms.

Part 5
Preparing to Create a Professional Index

  1. 1
    Skim or read the text. It's best to have some familiarity with the subject you're indexing, so that you know what terms or concepts are important in the text. If you didn't write the work you're indexing, do some skimming or pre-reading before diving in to ensure you are aware of the key terms and concepts in the work.[34]
    • If the text is not yet complete, you can still begin the process of building an index as long as the text has most of its final structure.
    • If you're collecting page numbers by hand, finish editing and modifying the text first, as an edit could push a particular section or subject onto another page.
  2. 2
    Determine your indexing source. Maybe you are going to be using page proofs to do your indexing, or a printed PDF of the original document, or you may feel comfortable indexing directly from the computer screen. The method you choose will depend on what type of text you are indexing and whether you prefer having hard copies in front of you as you index or are fine working off a screen.[35]
    • If you are indexing a printed book, you must use the final page proofs, in the final layout, to create the index. If the pagination is not final and you don’t use the final page proofs, you may end up having to re-index the entire book.
    • Using a searchable PDF version of the text will prevent you from accidentally deleting or altering the book’s text or layout. It will also make it easy for you to search additional occurrences of words or phrases elsewhere in the book, ensuring a comprehensive listing of entries.
    • You may prefer to just index directly from the computer screen, rather than a marked up hard copy, but it may be more difficult for you to comprehend the text on screen and to locate keywords and concepts in the text. So perhaps avoid this method if you are indexing a complex or very long book.
  3. 3
    Confirm the length of the index with the publisher. Before you start to compile the index, you need to know how many pages the publisher has allotted for the index, and how the index is going to be laid out.[36]
    • Many variables can affect the length of an index, such as the average number of index entries per a page, as well as the typography and layout of the index. So discuss these details with the publisher.
  4. 4
    Check with the publisher about their style guide. It’s important you understand the style requirements from the publisher of the text so you then know how to format the index.[37]
    • The primary style guide is the Chicago Manual of Style, 16th edition[38]. However, certain publishers may have preferences for page numbers, alphabetizing, handling of headings, pictures, tables and figures in the text, etc. So always discuss these details with the publisher, if possible, before you start indexing.
  5. 5
    Check if you have access to indexing software programs. Most professional indexers use software to automate certain tasks, but these programs can be expensive and take time to learn and master.[39]
    • Don’t worry too much if you don’t have access to indexing software as you can also use a word processing program like Microsoft Word to enter terms and page numbers.
    • A word processor with an indexing tool can keep track of the page numbers for you and update the index automatically if the text changes.
  6. 6
    Manage your time, based on your indexing experience. Keep in mind indexing is a time consuming process. How much time you spend on indexing will depend on how experienced you are at indexing. So be prepared to spend a certain number of hours or days on the index, depending on the text, and plan your time accordingly.[40]
    • For example, a 300 page text may take an experienced indexer 7 days to complete and a beginner indexer 2 weeks to complete.[41]


  • Before you begin indexing, refer to a completed index in another work, especially if you are new to indexing. Examine how the completed index is structured and formatted.
  • Consider hiring somebody to compile your index for you. Various freelancers and services will index a text, for a fee. If you do hire somebody, choose an indexer with some understanding of the topic in question.
  • If you're a copy editor, you will not usually get to read the index because it is usually created after you've participated in the production process.[42] But if you're a proofreader, you will be expected to read the index very carefully and check that its references are all accurate.

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