How to Choose the Best Amazon KDP Niche (and Spy on Categories Your Competitors Use)

Are you starting to wonder what niche you should publish in on Amazon?

If you feel more confused than ever about choosing the right niche for your self-publishing business, you’re not alone. One of the most common questions new authors ask is:

“What niche should I publish in?”
And right after that comes the big one:

“Can I actually predict sales?”

In this guide, we’ll break down niche research clearly and practically. You’ll learn how Amazon categories work, how to research profitable niches, and a powerful bonus method to uncover hidden competitor categories.

Let’s dive in.

What Is a Niche in Self-Publishing?

In self-publishing, a niche simply means:

A specific audience
A specific type of content that the audience is searching for

Niches are usually defined by two things:

Keywords readers type into Amazon
Categories where your book gets placed

While keywords are important, this article focuses mainly on categories because categories play a huge role in how your book gets discovered.

Why Categories Matter So Much on Amazon

Think of Amazon like a giant digital library.

In a library, books are organized through systems so readers can find exactly what they want. If everything was thrown randomly into one pile, customers would never find the right book.

Categories do the same job on Amazon.

Amazon wants books placed into the most relevant and specific category possible so that buyers can discover them easily.

That’s why picking the right niche category is one of the most important decisions you’ll make when publishing.

Where to Find a Book’s Categories on Amazon

If you visit any book’s product page on Amazon, you can scroll down to the Product Details section.

There you’ll see information like:

ASIN or ISBN
Best Seller Rank (BSR)
Categories the book is listed in

One important note from the script:

If a book has zero sales, Amazon may not show category rankings yet.
But you can still research categories by looking at other books in the niche.

BISAC Categories vs Amazon Categories (What’s the Difference?)

When publishing through KDP, authors select categories from the BISAC system.

BISAC Categories

BISAC stands for Book Industry Standards and Communications.

Used as a publishing standard in the US and Canada
Contains nearly 4,000 categories
Authors can choose 2 categories inside the KDP dashboard

Amazon Categories

Amazon has its own browsing system:

Around 16,000 categories
Much more detailed than BISAC
Amazon places books into deeper niche paths automatically

This explains why the category you select in KDP may not look identical on Amazon’s storefront.

Quick Comparison Table

Feature	BISAC Categories	Amazon Categories
Used in KDP dashboard	Yes	No
Number of categories	~4,000	~16,000
Categories you can select directly	2	Not directly selectable
Category depth	Broad	Very niche and layered
Category placement	Manual selection	Algorithm + browse paths

You Can Have Up to 10 Categories on One Book

Many authors don’t realize this:

Even though you choose only 2 categories in KDP, you can actually have up to 10 categories attached to one title.

The additional 8 categories can be added by contacting Amazon KDP support through:

Contact Us → Book Details → Categories & Keywords

You provide your ASIN/ISBN and request the specific browse paths you want.

How to Research Profitable Niches (Two Proven Methods)

The transcript explains two main ways to research categories.

Method 1: The “Grind It Out” Approach (Free)

This is the traditional, manual way.

Step 1: Search for a Keyword Related to Your Book

Example:

“Workout Plans for Men”

Step 2: Click a Competing Book

Scroll down and look at its Product Details.

Step 3: Click the Category Link

This takes you to that category’s bestseller list.

Step 4: Study the Top 20 Books

The key metric used in the video is the Best Seller Rank (BSR).

The speaker suggests looking for categories where:

The top books are ranked under 100,000

That shows proof of concept: people are buying books in this niche.

If the #1 book is ranked at 500,000, that niche may not have strong demand.

Method 2: Publisher Rocket (Faster Category Research)

Instead of manually checking bestseller lists, the video recommends using Publisher Rocket.

Publisher Rocket helps authors:

Find category opportunities quickly
View category rank metrics instantly
Discover related categories without endless clicking

It removes much of the manual research work involved in niche selection.

Can You Predict Sales in a Niche?

This is where the transcript is very honest:

No one can perfectly predict sales.

Sales depend on many factors, including:

The quality of your content
Your audience
Your promotional strategy
Market trends that rise and fall over time

Some authors rely only on organic Amazon traffic, but the video warns that for most people, marketing is required.

Spy on Your Competitor’s Hidden Categories

This is one of the most valuable tricks shared.

Amazon now only shows the top few categories on a product page. But books may actually be listed in many more.

Here’s how to uncover the full browse path.

Step-by-Step Competitor Category Spy Hack

Go to any competitor’s book page
Scroll to Product Details
Copy the ASIN
Paste the ASIN into Amazon’s search bar
On the left sidebar, expand the category dropdowns
Keep clicking deeper until you reach the full niche path

This reveals sub-sub-niches such as:

Kindle eBooks → Health → Exercise & Fitness → Weight Training

You can repeat this process with any book in your niche.

Then, you can request those same browse paths through KDP support.

The speaker notes this is not unethical — it helps you categorize correctly.

Choose Niches Strategically, Not Emotionally

Amazon niche research doesn’t need to be confusing.

If you understand how categories work, study bestseller ranks for proof of demand, and use competitor browse paths, you can make smarter publishing decisions.

You may not predict exact sales, but you can absolutely publish in categories where readers are already buying.

That’s how you build a sustainable self-publishing business.

FAQs

What is the best way to choose a niche on Amazon KDP?

Focus on categories with proof of demand by checking bestseller ranks and studying similar books in your niche.

How many categories can one KDP book have?

A book can have up to 10 categories – 2 selected in KDP and 8 additional ones added through KDP support.

Can you predict sales in a niche?

No one can perfectly predict sales. Success depends on market demand, content quality, and marketing strategy.

What is the ASIN category spy trick?

By searching a competitor’s ASIN on Amazon, you can expand the left sidebar category tree to reveal deeper browse paths.