On Amazon KDP you can enter up to seven keywords or short phrases and choose up to three categories for each format of your book. The right choices are the words real readers type into Amazon search and the categories where your book genuinely belongs and can be seen. Research them with Amazon’s own search bar and category listings first, follow KDP’s metadata rules strictly, and review them after launch.

This guide includes a few product links near the end. As an Amazon Associate, Freyja Publishing earns from qualifying purchases, at no extra cost to you.

This guide walks through how KDP keywords and categories work today, what KDP prohibits, a repeatable research method using Amazon itself, how paid research tools fit in, and a checklist you can follow for every new title.

At a glance

• Seven keyword boxes, each holding a word or short phrase. KDP’s metadata guidelines suggest phrases of two to three words.
• Up to three categories, chosen directly in your Bookshelf under the book’s details. Changes can take up to 72 hours to appear.
• Do not repeat words already in your title, contributors or categories, and avoid other authors’ names, brands you do not own, Amazon programme names and promotional terms.
• Amazon search is your best free research tool: its suggestion drop-down shows what readers actually type.
• Keywords and categories can be changed as often as you like, so treat them as something to test, not set and forget.

How keywords and categories work together

Keywords and categories do different jobs. Categories are the shelves your book sits on when readers browse. Keywords help Amazon match your book to searches and, according to KDP’s categories help page, also help Amazon decide where to shelve your book, particularly when no category fits exactly. Keywords are usually more specific than categories: a category might be a broad romance subgenre, while a keyword describes the trope, setting or tone.

Neither will rescue a book that does not satisfy readers. Your title, cover, description and reviews still decide whether a reader clicks and buys. Think of keywords and categories as making sure the right readers see the book at all. Our guide to marketing a self-published book shows how to get those sales-page basics right before you spend on promotion.

The current KDP rules

Keywords

KDP’s help page on keywords allows up to seven keywords or short phrases, entered in the Keywords section when you edit a book’s details. Each box has a character limit shown in the field itself. KDP suggests including information that does not already appear in your title or description, such as:

• Setting (for example, a historical period or place)
• Character types (single dad, veteran)
• Character roles (strong female lead)
• Plot themes (coming of age, forgiveness)
• Story tone (dystopian, feel-good)

KDP also advises putting words in the order a reader would type them (its example is “military science fiction”, not “fiction science military”) and not using quotation marks, which narrow results.

Categories

Since 2023, KDP has used a direct selection process: you choose up to three categories for each format of your book from within KDP, rather than picking two and requesting more through support. This is still how it works at the time of writing (October 2026). Before choosing, KDP asks you to confirm your primary audience (including whether the book contains sexually explicit content) and your primary marketplace, because categories differ by marketplace and by format.

Some rules to know:

• If three categories are already selected, you must remove one before adding another.
• New categories can take up to 72 hours to show on Amazon.
• Children’s categories require a reading age between 0 and 12; Teen and Young Adult categories require a reading age of 13 to 17.
• Books marked as sexually explicit are not eligible for children’s categories.
• KDP may remove or change a category that does not match the book’s content, and Amazon updates its category lists over time.

What KDP does not allow in keywords

KDP states it has zero tolerance for metadata intended to advertise, promote or mislead. Its keyword help page and metadata guidelines list things to leave out. Breaking these rules can lead to content being removed.

Avoid	Example of what not to do	Why
Other authors’ names or books	A bestselling author’s name in your genre	Prohibited and misleading to readers
Brands you do not own	A trademarked product or franchise name	Prohibited unless you are authorised
Amazon programme names	Kindle Unlimited, KDP Select	Specifically listed as not allowed
Subjective or quality claims	Best novel ever	Not allowed and not how readers search
Time-sensitive or promotional terms	New, on sale, free, available now	Not allowed
Sales rank references	Number one bestseller	Not allowed
Words already in title, contributors or categories	Repeating your series name	Wastes space
Spacing, plural or capitalisation variants	“vampire” and “vampires”	KDP treats these as duplicates
Generic words	Book, novel	Common to every listing
Unrelated content or HTML tags	Popular search terms unrelated to the book	Not allowed

The same thinking applies to your title and subtitle. KDP’s metadata guidelines say the title field should contain only the actual title as it appears on the cover, and that title and subtitle together must be under 200 characters. Stuffing keywords into a subtitle risks your listing being changed or removed.

How to research keywords using Amazon search

You do not need a paid tool to start. Amazon’s own search shows you how readers phrase their searches. Use the store for your primary marketplace, and ideally a private or logged-out browser window so your own browsing history influences results less.

1. List what your book is. Write down the genre, subgenre, tropes, setting, character types, themes and tone. Aim for 20 to 30 candidate words and phrases.
2. Use the search suggestions. Select the Kindle Store or Books department and start typing each idea slowly. The suggestion drop-down shows phrases shoppers commonly search. Note the ones that genuinely describe your book.
3. Try the alphabet method. Type a core phrase followed by a space and each letter (for example, “small town romance a”, “small town romance b”) to reveal more suggestions.
4. Check the results. Search each candidate. If the books returned are similar to yours, it is a relevant keyword. If they are unrelated, KDP’s own advice is to adjust it.
5. Gauge competition. Look at the top results. If every listing has thousands of reviews and strong sales ranks, a newer book may struggle to appear; a slightly narrower phrase may serve you better.
6. Study comparable books. Look at the titles, subtitles and descriptions of recent books similar to yours. Note the words that recur, but never copy other authors’ names or titles.
7. Fill the seven boxes. Choose the most relevant, distinct phrases. Do not repeat words across boxes or from your title.

How to choose your three categories

Category choice is about relevance first and visibility second. A reader who finds your sweet romance in a steamy category will be disappointed, and that shows up in reviews.

1. Confirm audience and marketplace. Set your primary audience and primary marketplace in KDP before opening the category menu.
2. Browse the store as a reader. Open the bestseller lists for your genre on your primary Amazon marketplace and drill down through the subcategories.
3. Look at books like yours. On comparable books’ product pages, the “Best Sellers Rank” section shows some of the categories they appear in.
4. Compare category size and competition. Check the sales rank of the books at the top and lower down each bestseller list. A smaller, well-matched subcategory can give a new book a better chance of being seen than a very large one.
5. Pick a mix. Many authors choose one broader category that defines the genre and two narrower ones that describe the book precisely.
6. Repeat for each format. Ebook and print categories are chosen separately and the lists can differ.

KDP Support will not recommend categories for you, so this research is your job. If the category you want does not exist, choose the closest match and let your keywords carry the detail. Knowing what readers expect from your genre makes this easier, and how genre changes the best way to publish explains those expectations genre by genre.

A worked example

Imagine a light-hearted romance set in a coastal fishing village, where a single father falls for the new veterinarian. Instead of keywords such as “romance book” or “best new romance”, a stronger set might cover the elements a reader searches for: a small-town setting, a single-dad hero, a second-chance or slow-burn trope if it applies, a seaside setting, a feel-good or clean tone, and a profession-based phrase. Each would be checked in Amazon search to confirm that similar books appear. For categories, the author might choose one broad contemporary romance category plus two narrower ones that match the small-town and tone elements, after checking each on the bestseller lists.

Notice what the example leaves out: no other authors’ names, no “Kindle Unlimited”, no plural duplicates, and nothing already in the title.

Where research tools fit

Paid tools such as Publisher Rocket, and browser extensions that read Amazon data, can speed up research by estimating search volume, showing competing titles and listing categories. They can save time if you publish often. Keep in mind:

• Their search-volume and sales figures are estimates, not data from Amazon.
• They do not change KDP’s rules; you still need to check each keyword for relevance.
• Check the current price, refund terms and whether the tool covers your marketplace before buying.
• The free method above covers the essentials for a first book.

For a wider comparison of software and services, see how to choose the right author tools. Keyword research also feeds directly into advertising; if you plan to run ads later, our guide to Amazon Ads for authors explains how to use these keywords without losing money.

Common mistakes to avoid

• Choosing categories for rank rather than fit. An obscure, unrelated category can earn a bestseller badge but puts your book in front of the wrong readers, and KDP may remove it.
• Wasting boxes on repeats. Words already in your title, author name or categories add nothing.
• Using single generic words. “Romance” or “fantasy” on their own compete with millions of listings.
• Copying another author’s metadata. It is prohibited when it uses their names, and it rarely describes your book well.
• Setting and forgetting. Reader language and Amazon’s categories change; review your choices every few months.
• Inconsistent formats. KDP recommends keeping keywords and descriptions consistent across ebook and print editions.

Your launch checklist

• Primary audience and primary marketplace confirmed
• 20 to 30 candidate phrases listed from what the book actually contains
• Each candidate checked in Amazon search for relevant results
• Seven distinct keywords entered, none repeating the title, contributors or categories
• No other authors, brands, programme names or promotional words
• Three categories chosen per format, each one an honest match
• Calendar reminder set to review keywords and categories after launch

If you are publishing for the first time, the complete guide to self-publishing your first book puts this step in context, and how to find a profitable niche helps you understand which reader searches to target before you write. A simple routine for watching market trends in your genre makes these reviews quick.

Sources this guide draws on: Kindle Direct Publishing help pages “Make Your Book More Discoverable with Keywords”, “KDP Categories” and “Metadata Guidelines for Books”, together with Amazon’s public store search and bestseller lists.

Frequently asked questions

How many keywords can I use on KDP?

You can enter up to seven keywords or short phrases per book format. KDP’s metadata guidelines suggest phrases of two to three words, and each box shows its own character limit.

How many categories can I choose on Amazon KDP?

You can choose up to three categories per format, selected directly in your KDP Bookshelf. The process was introduced in 2023 and remains current at the time of writing; changes can take up to 72 hours to appear.

Can I change my KDP keywords and categories after publishing?

Yes. KDP says you can change keywords as often as you like, and you can edit categories through the book’s details. You need to republish after saving, and category changes are reviewed and can take up to 72 hours to show.

Should I repeat words from my title in my keywords?

No. KDP advises against repeating information already in your title, contributors or categories. Use the boxes for different words readers might search.

Can I use another author’s name as a keyword?

No. KDP prohibits names of authors not associated with your book, along with brands you are not authorised to use. It can remove metadata that breaks these rules.

Do I need a paid tool to find KDP keywords?

No. Amazon’s search suggestions and bestseller lists give you enough to choose solid keywords and categories. Paid tools can save time but provide estimates, so check their results against Amazon search.

Good keywords and categories come from knowing your book and your readers, then confirming your choices in the store where they shop. Follow KDP’s rules, use Amazon’s own search to test every idea, and come back to your metadata regularly, and your book will have the best chance of appearing in front of readers who will love it.