KDP Keywords and Categories in 2026: How to Choose Them (From Amazon's Own Rules)

KDP lets you enter up to seven keywords or short phrases and choose up to three categories for each book, and those, along with your title and sales history, tell Amazon where to show it. Amazon's help pages spell out what's allowed and what's banned more precisely than most guides admit. This post quotes those rules directly, flags where Amazon contradicts itself, and gives you a research method that needs nothing but the Amazon store.

What KDP keywords are, and what they actually do

Keywords are the hidden search terms you enter during title setup. Amazon's keyword help page puts their role modestly: "Along with factors like sales history and Amazon Best Sellers Rank, relevant keywords can boost your placement in search results." They are one input among several, not a lever that overrides sales.

Amazon's separate Search Results page lists what else influences search: past sales history, availability, how long the item has been listed and popularity. It also says plainly that neither Amazon nor KDP can guarantee where your book shows up. Keywords get you considered for a search; readers' behavior decides where you rank.

The seven boxes and the character limit

The help page's instruction is to "Use up to seven keywords or short phrases" and to "Keep an eye on the character limit in the text field." KDP doesn't print the number on that page, which is why you'll see it argued about. The form itself enforces the limit as you type. Third-party guides describe it consistently; Reedsy's guide, updated in August 2026, says each keyword can be "a short phrase of up to fifty characters." Trust the counter in your dashboard over any article, including this one.

Keywords are set per format. KDP's instructions have you open "Edit book details for your book format," and the help page asks you to keep keywords and description consistent across physical, ebook and audio editions.

Amazon's keyword rules, quoted

Amazon publishes two lists that overlap: the keywords page and the Metadata Guidelines for Books. Between them, here is what to avoid.

Prohibited outright

The metadata guidelines say "We do not tolerate keywords that mislead or manipulate our customers" and list prohibited references to:

• Other authors
• Books by other authors
• Sales rank, such as "bestselling"
• Advertisements or promotions, such as "free"
• Anything unrelated to your book's content
• HTML tags

The keyword page's list of keywords to avoid adds anything misrepresentative, such as "the name of an author not associated with your book," brands you don't own or aren't authorized to use, and "Amazon program names like as 'Kindle+' or 'KDP Select'." The page already uses the new name Amazon gave Kindle Unlimited in October 2026; we'd leave the old name out too.

Also on Amazon's avoid list

The same keyword page lists terms that aren't framed as misleading but that, in our view, mostly waste a box:

• Information already in your metadata, such as title or contributors
• Words already in your categories
• Subjective quality claims ("best novel ever")
• Time-sensitive statements ("new," "on sale," "available now")
• Words common to most items in the category ("book")
• Spelling errors
• Variants of spacing, punctuation, capitalization and plurals ("computer" and "computers")
• Quotation marks

The exception on variants is words translated more than one way; Amazon's example is "Hanukkah" or "Chanukah," where both spellings are fair.

What Amazon recommends instead

The help page names five useful keyword types, each with an example: setting (Colonial America), character types (single dad, veteran), character roles (strong female lead), plot themes (coming of age, forgiveness) and story tone (dystopian, feel-good). It also asks you to "Combine keywords in the most logical order," with the example that shoppers search "military science fiction," not "fiction science military."

How KDP categories work in 2026

Amazon's KDP Categories page describes categories as "like digital shelves." The current rule is simple: "you can select 3 categories when creating a book in KDP." Those categories, along with your keywords, tell Amazon where to shelve the book. New choices "can take up to 72 hours" to display.

The 2023 change

This is the part older guides get wrong. In early 2023, KDP worked differently. An archived copy from March 2023 shows the help page saying "you'll choose two Browse Categories from a list" based on BISAC codes, after which Amazon placed the book into its own store categories. By December 2023, the same page said "You can now choose three Amazon Store categories based on primary marketplace for each title during setup."

So the change was from two industry-standard BISAC codes to three actual Amazon store shelves you pick directly. The December 2023 page added that "we are no longer accepting requests to add or update categories," so advice to email KDP support for extra categories is out of date. The current page says the support team "cannot give you specific recommendations or strategies for picking book categories."

Primary marketplace and reading age

You choose categories for your primary marketplace, so set that field first. Per the metadata guidelines, "You must select a primary marketplace in order to select categories." Categories also differ by format and by store, and some aren't available for every format.

Children's and teen categories depend on reading age. The categories page says to set reading age to 0–2, 3–5, 6–8 or 9–12 for Children's categories, and 13–17 for Teen & Young Adult. Answering yes to the sexually explicit images or title question makes the book ineligible for Children's categories, and the search troubleshooting page adds that such books "will not surface in general product searches."

When Amazon overrides you

Amazon keeps the final say. The categories page warns that it may remove or change an unrelated category, and gives the example of a book on Canadian national parks placed in Science Fiction. The metadata guidelines say "We do not tolerate selecting categories to mislead or manipulate our customers."

Browse categories vs search: two different ways readers find you

Categories and keywords serve two different shopping behaviors. A reader who clicks through Kindle Store > Romance > a subgenre is browsing; a reader who types "enemies to lovers fae romance" is searching. Categories put you on the shelf for browsers. Keywords, title and description make you a candidate for searchers.

Amazon connects the two in one useful line on the categories page: "If you're not finding a specific category to place your book in, you can use keywords to help us determine how we 'shelve' your book." When no category fits your niche precisely, a keyword describing that niche is the tool Amazon points you to.

Search also collapses formats. The troubleshooting page says Amazon "generally displays only one format for each book in search results," so don't panic if your paperback appears instead of your ebook.

A+ Content: Amazon doesn't list it as a ranking factor

A+ Content gets a lot of attention in launch advice. Amazon's A+ Content page describes it as images, text and comparison tables added to your detail page "to engage readers and give them more information as they consider buying your book," and notes that "most readers will need to scroll to view the content."

None of Amazon's keyword, category or search pages lists A+ Content as a discovery factor. Our reading: A+ helps a shopper who has already found your page decide to buy, which can help sales and, through sales, rank. It is not a place to hide more keywords. The A+ guidelines even warn that image alt-text, "previously known as image keywords," that doesn't describe the image can get the content rejected.

A research method that uses only Amazon

You don't need a paid keyword tool to do this well. Amazon's own help page describes the core loop: search your candidate keywords on Amazon, "look at the suggestions that appear in the 'Search' field drop down," and change anything that returns "irrelevant or unsatisfying results."

Step by step

1. Describe your book in Amazon's five keyword types. A worked example: a cozy fantasy about a retired adventurer who opens a bakery. Setting: small town, fantasy village. Character types: retired adventurer, orc heroine. Roles: found family. Themes: second chances. Tone: cozy, low stakes, feel-good.
2. Test each phrase in the Kindle Store search box. Type "cozy fantasy" slowly and note what Amazon suggests next. Autocomplete shows phrasing real shoppers use; it doesn't tell you how competitive a phrase is.
3. Judge the results page. If "cozy fantasy found family" returns books with covers and blurbs like yours, it's a good neighborhood. If it returns cookbooks, drop it.
4. Pull categories from comp titles. Open three to five books you'd list as comps and note the categories in each detail page's Best Sellers Rank. Our guide to finding comp titles covers how to choose books that are recent and genuinely comparable.
5. Choose your three categories. Amazon's own tip is to "Balance popularity and relevance." Our practice is one broader shelf and two more specific ones, all accurate.
6. Write the seven boxes and audit them against the checklist below. For the bakery example, that might be: found family second chances; retired adventurer; low stakes village; orc heroine slice of life; feel-good bakery story; and two more from your list. If Cozy Fantasy is already one of your three categories, leave "cozy" and "fantasy" out of the boxes, since Amazon lists words already in your categories as wasted space.

Your blurb should use the same language naturally. KDP's guidelines ban keyword lists in the description, so write it for readers; our book blurb guide shows how. If you're unsure which subgenre labels your readers use, our genre hub lists them.

Five mistakes that waste your metadata

Each of these comes straight from Amazon's pages.

1. Comp authors in the boxes. "For fans of" another writer feels like targeting; the metadata guidelines list references to other authors as prohibited. Put comps in your marketing, never in your keywords.
2. A keyword list in the description. The guidelines say KDP cannot accept "Any keywords or book tags phrases" in the description, along with reviews, URLs and time-sensitive information.
3. A keyword-stuffed subtitle. The title field should hold only the title as it appears on the cover, and title plus subtitle must be fewer than 200 characters. The keyword page adds that customers "are more likely to skim past long titles (over 60 characters)."
4. Plurals and spellings in separate boxes. Amazon treats "computer" and "computers" as variants to avoid, so spend that box on a new idea.
5. Constant category changes. The March and December 2023 versions of the categories page warned that if you change categories frequently, your book's historical customer activity "may be recalculated," which could affect sales rank. The current page doesn't repeat that line, but a 72-hour display delay is reason enough to change categories deliberately.

After launch: keywords aren't permanent

Amazon says "You can change keywords and descriptions as often as you like." Categories are different: each change can take up to 72 hours to appear, so make changes deliberately and give each version time before judging it. Re-run step 2 every few months, since autocomplete suggestions can change with what shoppers type.

Price affects how your book converts once readers find it; see our ebook pricing guide for Amazon's current royalty bands. And if you're deciding between KDP Select and selling wide, that choice changes which stores your metadata needs to work in; see Kindle Unlimited vs going wide.

The short version of Amazon's rules: describe your book accurately, in words readers actually type, and don't mention anyone else's.