BISAC codes explained: how to choose subject codes for your book

BISAC codes are the subject codes the book trade uses to decide where your book goes: which shelf, which online category, which search filter. A code like FIC031000 stands for “FICTION / Thrillers / General”. This guide explains how the codes work, how many to pick, shows five example books with their BISAC and Thema codes, and clears up how all of this relates to your categories on Amazon KDP.

What BISAC codes are for

Every book that goes into the trade needs a machine-readable subject. Retailers build their categories from it, bookshops use it to stock themed tables, and library and store search systems filter by it. A vague code puts your book on the wrong shelf, where the right readers never see it.

Where you need which code:

How a BISAC code is built

BISAC stands for Book Industry Standards and Communications. The list is maintained by the Book Industry Study Group (BISG) and free to browse. Each code has three letters for the main section and six digits, plus a heading that reads from general to specific:

• FIC031000: FICTION / Thrillers / General
• SEL023000: SELF-HELP / Personal Growth / Self-Esteem
• CKB055000: COOKING / Regional & Cultural / Mediterranean

BISG's own guidance comes down to three rules. Use no more than three codes per title, and fewer if they already describe the book. Use the most specific code possible, and don't add a general heading next to a specific one. The first code is the primary code and should be the book's main subject. IngramSpark puts it more bluntly: avoid General codes whenever possible.

Thema: the international counterpart

Thema is published by EDItEUR and maintained by an international committee. Its codes are language-independent: FH means thriller and suspense fiction in every language, and the more letters, the more specific (FHX is psychological thriller). Qualifiers add places, languages or audiences. If you distribute outside the US, expect to be asked for a Thema code alongside or instead of BISAC.

Five example books with their codes

Here is how the five example books would be coded (the first code is the primary one):

Two things stand out. The schemes don't map one to one: BISAC has a heading for self-esteem, Thema files the same book under popular psychology. And a second code is worth adding only when it adds information, like “Bedtime & Dreams” for the picture book. For the thriller, a second thriller code would add nothing.

Amazon KDP: three categories from Amazon's tree

KDP doesn't ask for BISAC. You select three categories directly from Amazon's category tree: category, subcategory and placement. Categories vary by marketplace and format, and not every category is available for every format. Amazon doesn't allow categorization that misleads readers and may change or remove a category that doesn't match the book.

On Amazon, competition matters as much as accuracy. In a small, fitting subcategory a few sales a day can be enough for a top spot. How many exactly, the sales rank of the books at no. 1 and 2 in that category tells you.

Common BISAC mistakes

1. General codes. FIC000000 “FICTION / General” tells the trade nothing. Almost every book has a more specific code.
2. Three codes that say the same thing. Three thriller variants don't make a book more visible, they dilute it.
3. Wrong audience. A children's book belongs under JUV (Thema Y), not FIC (Thema F).
4. Popular instead of accurate. A busy category the book doesn't fit brings disappointed readers.
5. Mixing up Amazon and the trade. BISAC and Thema are for distributors and bookshops; Amazon categories are chosen separately on KDP.

Categories, ranks and codes in one go

The Bookfairy category research gives you both at once: fitting Amazon categories for your marketplace (eight Amazon stores to choose from) with the current rank of the books at no. 1 and 2, plus Thema and BISAC for distributors and the book trade. Everything comes as text to paste and as a CSV. You see the first suggestion for free; the full research costs $4.2035 tokens. For KDP's seven keyword boxes there is the keyword research.