August 22, 2026
A back-of-book index is the difference between a nonfiction book readers browse once and one they keep on the shelf as a reference. This guide walks through building one yourself in 2026, whether you're working in Microsoft Word or handing files to a professional indexer before your final print run.
Readers of nonfiction — history, memoir, how-to, reference, business books — use the index to find one fact fast. No index, and a reader who can't locate the one section they need puts the book down and doesn't come back. Reviewers and librarians notice a missing or sloppy index too; it signals a rushed self-publishing job. Getting the index right is part of what separates a book that reads like a nonfiction reference tool from one that just looks like a manuscript with a cover slapped on it.
The index belongs in your back matter, after the appendix and bibliography, and it's usually the last piece of front-to-back content you build before sending files to print.
If your manuscript still needs structural work before this stage, sort out your table of contents and full front matter order first — indexing is a back-matter task and should come after those are locked.
This is the step every guide to how to create a book index skips, and it's the one that breaks the most projects. Index entries reference exact page numbers, so any edit that shifts text — a deleted paragraph, a resized image, a new chapter break — invalidates every entry that follows it on the page. Treat your manuscript as frozen the moment you start marking entries in 2026. Common mistake: authors keep fixing typos mid-index and end up re-indexing the whole back half of the book.
Go chapter by chapter and pull out proper nouns, technical terms, named concepts, and anything a reader would plausibly search for. A business book needs terms like cash flow and customer acquisition cost. A memoir needs names, places, and named events. Aim for comprehensiveness over cleverness — an index with too few entries fails the reader more than one with a few extra. This step alone can take longer than the actual marking.
In Word, place your cursor after the relevant word and insert a mark-entry field (Alt+Shift+X on Windows), which generates an XE field code you can edit before generating the index. In InDesign, use the Index panel to add topics directly and build a hierarchy of entries and subentries as you go. Mark every occurrence you want indexed — Word and InDesign only pull page numbers from marked instances, not from a keyword search across the file.
Real-world index terms rarely map to a single spelling or name. Add See references for alternate terms readers might search first (Vitamin D, see also Cholecalciferol) and See also references between related topics. Skipping this is the single biggest reason self-published indexes feel thinner than traditionally published ones — cross-references are what make an index feel navigable instead of just alphabetical.
Once every entry is marked, generate the index (References then Index then Insert Index in Word; Generate Index in InDesign's panel). Choose a two-column layout for most trim sizes — it reads faster and fits more entries per page. Set subentries to indent consistently and confirm page ranges (45-52) render correctly rather than listing every page individually.
Do this after your file is exported as a print-ready PDF, not before. Page numbers can shift during PDF export in ways they don't inside your word processor. Read every entry against the actual printed page number — twice. This is the step that catches an index pointing readers to the wrong chapter entirely.
Place the finished index at the very end of your back matter, after acknowledgments and any appendices. Confirm your margins and trim size match the rest of the interior before final export — an index formatted for a 6×9 trim will look cramped or oddly spaced if your book prints at 5.5×8.5.
Publishing Xpress prints nonfiction titles with a completed index sitting in the back matter every week, and the projects that go smoothest are the ones where the index was built against a genuinely final file — not a draft that got one more edit after indexing started.
Once your index is generated and placed, don't send the file straight to print. Run it through a full proofing pass before sending it to print — index entries are exactly the kind of detail a fast final read misses, and a wrong page number in the index undercuts the whole reference value of the book.
What’s the best way to create an index for a nonfiction book?
For most self-publishers in 2026, Word’s built-in mark-entry (XE field) tool is the best starting point — it’s free, works on a locked final manuscript, and handles straightforward nonfiction without extra software. Books with heavy cross-referencing or 400+ pages do better in InDesign.
Is Word’s built-in index tool good enough for self-publishers?
Yes, for most nonfiction projects Word’s XE field indexing is sufficient. It falls short on books needing complex nested subentries or extensive cross-referencing, where InDesign’s dedicated Index panel handles the hierarchy more cleanly.
How much does professional book indexing cost?
Professional indexers typically quote per page or per hour rather than a flat fee, and rates vary by project complexity. Get a direct quote from an indexer for your specific page count rather than assuming a standard rate.
How long should a book index be?
A nonfiction index typically runs 4-6% of the book’s total page count. A 300-page book usually needs a 12 to 18 page index; shorter books scale down proportionally.
Can I index my book in InDesign instead of Word?
Yes, and InDesign’s Index panel handles complex hierarchies and cross-references better than Word’s XE fields. It’s the better choice for reference-heavy nonfiction or books over 400 pages.
Do ebooks need an index?
Ebooks rely on search and don’t require a traditional page-number index, but a well-built index still adds value if you’re producing a print edition alongside the digital one. Most nonfiction authors build the index for the print run specifically.
When should I create the index — before or after final proofing?
Build the index after your manuscript’s pagination is completely locked, then proofread the index itself against your final print-ready PDF. Indexing on a file that still might change guarantees you’ll redo the work.
What’s the difference between an index and a table of contents?
A table of contents lists chapters and sections in the order they appear, front to back. An index lists specific terms, names, and concepts alphabetically with page references, letting readers jump straight to a topic regardless of which chapter it’s in.
The 4-6% length guideline isn't a suggestion to hit a quota — it's a signal. An index that comes in well under that range usually means passing mentions got skipped along with the trivial ones, and readers will notice the gaps exactly where they go looking for something specific. Build the term list generously in step two, and the rest of the process gets easier, not harder.
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