How to Research KDP Categories for Your Book

Most authors pick categories in a hurry at the end of the upload form. It is one of the last things you do, so it feels minor. But categories decide which shelves your book sits on, and which books it sits next to. That is worth ten minutes of real thought.

This guide gives you the method, so you can do it by hand if you like. Then I will show how AuthorScout speeds it up, and where the limits are.

Why categories matter

Think of categories as shelves in a very large bookstore. Readers who browse by subject find books through them, and Amazon uses them to organize its best seller lists.

Here is the rule of thumb most publishers work with, and I want to be clear it is a rule of thumb, not a statement about how Amazon ranks anything. A book placed in a category that matches its subject is easier for the right readers to find. And the books already high in that category show you what you are up against. A category where the top books sell strongly is harder to rank near the top of than one where the top books sell modestly.

So there are two questions. Does my book belong here, and how hard is it to stand out here?

The step-by-step method

Step 1: Start from your book idea

Write one or two sentences on what the book is, who it is for, and the problem it solves. Include your subtitle if you have one. Categories should describe the book as it is, so get that clear first.

Step 2: Find candidate categories

Build a list of categories that could fit. Three ways to do it:

• Look at comparable books. Open a few books written for your readers and see which categories they list, near the bottom of the product page under Best Sellers Rank.
• Browse the category tree. Work down from the broad subject into narrower ones. The specific paths often fit better than the broad ones.
• Check both formats. Kindle and paperback can have different category options and different competition.

Also note which store you are publishing in. Category paths and competition can differ between Amazon marketplaces.

Step 3: Look at the top books and their ranks

For each candidate, open the list and look at the books at the top. Write down the Best Sellers Rank (BSR) of the book at position 1, position 10 and position 50. Those three numbers give you a rough picture:

• If position 1 has a very strong BSR, the leaders are selling well.
• If position 50 still has a strong BSR, the whole category is busy, which is harder to climb.
• If position 50 has a weak BSR, there may be room, but it may also mean few readers browse there. Low competition and low demand can look the same.

BSR is a position, not a sales number. Lower means more sales. Any conversion to estimated sales is an estimate, and it is fine to use it as a way of comparing categories, not as a promise.

Step 4: Balance fit against competition

Now put the two side by side. A simple way: score each candidate for fit (does a reader browsing here expect a book like mine?) and for competition (how strong are positions 1, 10 and 50?).

The best choices are usually a good fit with manageable competition. If you have to choose, fit wins. A category that does not describe your book may send the wrong readers to it.

Step 5: Write down 2 or 3 choices

Pick your top two or three and keep a note of why. KDP allows a limited number of categories at upload, and the rules change, so check KDP's current limits and the current process on the KDP help pages before you commit. If you have more good options than slots, keep the best-fitting ones.

Step 6: Check again before upload

Categories are not fixed. Amazon can rename, merge or restructure them, and the books in them keep changing. Re-check your shortlist just before you upload, and again a few months after launch if you are able to adjust.

Common mistakes

• Choosing a category the book does not fit. It is tempting to choose a category because it looks easy. If readers there expect something else, the placement does not serve you.
• Chasing the lowest competition label alone. A quiet category can be quiet because few people shop there. Competition is a signal, not a verdict.
• Only checking one format. Kindle and paperback can look quite different.
• Judging by position 1 only. Look at positions 10 and 50 too.
• Setting it and forgetting it. Check again before upload.

Doing it by hand

You can do all of this for free. Search Amazon for comparable books, scroll to their rank section, and click through each category link. Then open each list, and note the BSR of the book at each position you care about. Put it all in a spreadsheet.

It works. It also takes a long time. For each candidate you may be opening several pages and copying several numbers, and doing it separately for Kindle and paperback. If you check five or six categories across two formats, that is a lot of tabs. Honest advice: do it by hand at least once so you understand what the numbers mean.

How AuthorScout does it

AuthorScout's Category Research covers two ways in, depending on where you are starting from.

Category Search: start with your idea

Enter your title and subtitle, or a short description with the topic and intended readers. Category Search returns relevant Kindle and paperback matches, up to 20 per format. For each, you can review:

• The category path and how well it fits.
• Competition.
• Available BSR targets for positions 1, 10 and 50.
• BISAC codes, where available.

You can sort by best fit or filter by competition across the full set of matches, not just the page you are looking at. Results are shown ten at a time. A very specific book may return fewer than 20 matches.

Category Explorer: start with the market

Not every author has a settled book idea. Category Explorer lets you browse category paths by demand and competition in the marketplace you choose, so you can see where opportunities may sit before you commit to a topic. Category paths and competition can differ between stores and formats, and AuthorScout includes category trees for 12 marketplaces.

Plan limits

• Free: 5 category searches a month.
• Pro: 200 category searches a month. Pro covers the US, UK and Germany.
• Publisher Pro: 400 category searches a month.

A caution that applies to any tool: ranking targets and competition are research signals. They are not promises of rank or sales, and a low-competition category does not guarantee a bestseller. Choose categories that accurately describe your book.

If you are still shaping the idea, Profitable Titles shows books with demand signals and relatively few reviews, and Keyword Research helps with the phrases readers use.

FAQ

Should I include my subtitle when researching categories?

Yes, if you have one. A subtitle often describes the subject or reader more clearly than the title does.

Will every search return 20 categories?

No. Twenty is the most per format. A more specific book may have fewer relevant matches.

Is a low-competition category always better?

No. It may have little reader demand, or it may not fit your book. Fit comes first.

How many categories can I choose?

KDP sets a limit, and it can change. Check KDP's current help pages rather than relying on a number from a blog.

Do I need to check categories more than once?

It is a good habit. Categories and the books in them change, so check before you upload.

Where to go from here

Write your one-sentence description of the book, list five candidate categories, and note the BSR at positions 1, 10 and 50 for each. If you want to skip the tab-switching, run the same check in AuthorScout. Either way, choose with data, not guesses.