KDP Categories and Keywords: The Rules

Every KDP fact below comes from KDP's own help pages, read on 2026-10-20. KDP's pages give no figures on how categories or keywords change sales or ranking, so this guide doesn't either. KDP changes its rules, so check the linked pages before you publish.

Categories: how many and how to choose

KDP says book categories "are like digital shelves that organize books into specific genres and topics," and that "you can select 3 categories when creating a book in KDP." Its metadata guidelines say the same: during title setup you choose up to three categories from a list based on your primary audience and marketplace.

KDP lists three tips. Research your genre: look at where similar books are categorized and decide whether yours fits there. Pick accurate categories: irrelevant ones "create a poor shopping experience for readers." Balance popularity and relevance: aim for categories popular enough to have reader interest, but not so broad, or specific, that the book gets lost. KDP adds that its Support Team can't give specific recommendations for picking categories.

• Marketplace matters. Categories differ in each marketplace and aren't all available for every format. KDP says to focus on your primary marketplace and pick the best match across formats if needed.
• Set your audience first. Review Primary Audience and Primary Marketplace before choosing categories. The sexually explicit question must be answered, and a Yes makes the book ineligible for Children's categories.
• Reading age shapes eligibility. For Children's categories KDP lists the ranges 0-2, 3-5, 6-8 and 9-12. For Teen & Young Adult, set 13-17 (on Amazon.de it is 12-15).
• Low-content books must tick the Low-content box under Categories, or KDP says the book will be rejected. See our low-content guide.
• Timing. KDP says it can take up to 72 hours for a book to show in new categories.

Keywords: up to seven

KDP says relevant keywords "can boost your placement in search results on the Amazon Store," alongside factors like sales history and sales rank, and that keywords should accurately portray the book and "reflect the words customers will use when they search." Its best-practice list:

• Use "up to seven keywords or short phrases," and watch the character limit in the text field. KDP's page doesn't state the limit.
• Put words in logical order: customers search "military science fiction," not "fiction science military."
• Search Amazon with candidate keywords first. If results are irrelevant, change them. Look at the suggestions in the search box.
• Think like a reader.
• Use keywords for useful detail that won't fit the title and description: setting, character types and roles, plot themes, story tone.

KDP's two pages differ on length. Its keywords page says single words work better than phrases and specific words better than general ones. Its metadata guidelines say "for best results, we recommend using phrases that are 2-3 words long." KDP doesn't reconcile them, so treat phrase length as something to test by searching.

Setting and changing them

KDP describes the steps for each. For keywords, open your Bookshelf, click the ellipsis next to the book, choose Edit book details for your format, change the Keywords section, Save and Continue, then press Publish on the pricing page. For categories, open Edit details, review Primary Audience and Primary Marketplace, choose Edit categories or Choose categories, remove one if you already have three, pick the category, subcategory and placement, then save and submit the book for publication.

KDP says you can change keywords and descriptions as often as you like. After you submit category changes, KDP says it reviews them to make sure customers have a positive experience. If a category you chose later disappears, KDP's page says Amazon updates its categories from time to time, which may change what your book is listed under, and that you may need to wait for KDP's options to catch up when Amazon adds a new one. In the meantime it suggests the closest matching category. KDP's pages don't say how often categories change.

What not to put in keywords

KDP's keywords page lists what to avoid, and says the list "is not exhaustive" and that all keywords must comply with its Terms and Conditions.

• Information already in your metadata

  KDP's reason or example

  Title, contributors, and words already in your categories

• Subjective quality claims

  KDP's reason or example

  "best novel ever"

• Time-sensitive statements

  KDP's reason or example

  "new," "on sale," "available now"

• Words common to every item

  KDP's reason or example

  "book"

• Spelling errors

  KDP's reason or example

  KDP lists them outright

• Variants of spacing, punctuation, capitalization, plurals

  KDP's reason or example

  "80GB" and "80 GB"; "computer" and "computers"

• Misleading names

  KDP's reason or example

  An author not associated with your book; KDP has "zero tolerance" for metadata meant to advertise, promote or mislead

• Brands you don't own

  KDP's reason or example

  Or are unauthorized to use

• Quotation marks in search terms

  KDP's reason or example

  KDP says entering words without quotes lets customers find the book with any of those words

• Amazon program names

  KDP's reason or example

  "Kindle Unlimited" or "KDP Select"

• HTML tags

  KDP's reason or example

  KDP lists them outright

The metadata guidelines add: no references to other authors or other authors' books, to sales rank, or to promotions such as "free," and nothing unrelated to the book's content. The one exception on variants is words translated in more than one way. KDP also says you can change keywords as often as you like, and to keep them consistent across formats.

Keywords and the description work together. Our guide to writing a KDP book description covers what KDP's description rules say.