How to Choose KDP Keywords: Filling Amazon's 7 Keyword Boxes

When you publish on Amazon KDP, there’s a section with seven small boxes labelled “Keywords”. Most authors reach it at the end of a long upload, type in a few words that come to mind, and move on.

That’s a shame, because those boxes are one of the few places you directly tell Amazon who your book is for. Get them right and your book can turn up for searches that never mention your title. Get them wrong and you waste the space, or have them rejected.

Here’s how to fill them well, without paid tools or guesswork.

What KDP keywords actually do

When a reader types something into Amazon’s search bar, Amazon looks at your title, subtitle, series, author name, categories and these keywords to decide whether your book is a match.

Your title and author name are already searchable. The keyword boxes are your chance to add the other things readers search for: the setting, the type of story, the kind of main character, the mood.

A reader who doesn’t know your book exists won’t search for its title. They’ll search for something like “small town cozy mystery with a cat” or “enemies to lovers fantasy”. Your keywords are how you show up for those searches.

The rules: what Amazon won’t accept

Amazon’s keyword guidelines rule out a few kinds of words. Using them can get your keywords ignored, or your book flagged for changes:

• Sales claims, such as “bestseller”, “bestselling” or “#1”
• Promotional words, such as “free”
• Time-sensitive words, such as “new”, “new release” or “on sale”
• Amazon’s own programme and brand names, such as “Kindle Unlimited”, “KDP Select”, “Prime Reading”, or simply “Kindle” or “Amazon”
• Quotation marks and HTML tags
• Anything misleading: words about content that isn’t in your book, or other authors’ names and book titles

A few phrases sound banned but are fine because they’re genres or places. “New Adult” is a genre, and “New York” is a place. “Best friends” describes your characters, not your book’s quality. What matters is whether the word is a claim about your book or a description of what’s in it.

The space most authors waste

The most common keyword mistake isn’t breaking a rule. It’s repeating words Amazon already knows.

If your book is called The Lighthouse Keeper’s Daughter, putting “lighthouse” in a keyword box gains you nothing: your title already makes you searchable for it. The same goes for your author name, your series name, and words that appear in the categories you’ve chosen.

The same is true across the boxes. Putting “romance” in four of them doesn’t make you four times more findable. Each box should add something new.

So before you fill the boxes, write down what’s already covered: your title, subtitle, series and category names. Then spend your seven boxes on everything else.

What to put in the boxes instead

Amazon’s own advice is to think like a reader and describe your book from a few angles. A useful checklist:

1. Setting: where and when it takes place (“victorian london”, “small coastal town”, “space station”)
2. Character types: who it’s about (“single dad”, “female detective”, “retired soldier”)
3. Character roles and relationships: (“fake dating”, “rivals”, “found family”)
4. Plot themes: what happens (“second chance”, “missing person”, “heist”)
5. Tone and mood: how it feels (“cozy”, “dark”, “heartwarming”, “slow burn”)
6. Story tropes readers search for: the phrases your genre’s readers use (“enemies to lovers”, “chosen one”, “locked room mystery”)
7. Audience or comparison: who it’s for (“for fans of gothic suspense”)

You don’t need one of each, but working through the list stops you filling all seven boxes with versions of the same idea.

Use phrases, not single words

A box can hold a short phrase, not just one word, and phrases usually work better. Readers rarely search for “mystery”. They search for “cozy mystery with recipes” or “1920s murder mystery”.

A few practical points:

• Use the order a reader would type. “small town romance” rather than “romance town small”.
• Keep each box short. Amazon doesn’t publish an exact limit per box, but around 50 characters is the commonly reported working limit. If a phrase is getting long, split it across two boxes.
• You don’t need commas. Just type the words with spaces between them.
• Don’t add spelling variations or plurals. Amazon handles those itself.

Free ways to find the right phrases

You don’t need a paid keyword tool to find good phrases. These methods only take a browser:

Amazon’s search suggestions. Start typing a phrase into Amazon’s search bar, such as “cozy mystery with”, and look at the suggestions that drop down. They’re based on what people actually search for. Try different starts: “enemies to lovers…”, “fantasy with…”, “romance set in…”.

Books like yours. Look at the titles, subtitles and descriptions of successful books in your genre. Many authors work their key phrases into subtitles, like “A Small Town Second Chance Romance”. You can’t copy their titles, but you can notice the phrases that keep coming up.

Reader reviews. Readers describe books in their own words. If reviews of comparable books keep mentioning “slow burn” or “found family”, those are phrases readers think in, and probably search with.

Your own description. Read your book description and pick out the descriptive phrases. If a phrase is important enough to sell the book, it’s probably worth a keyword box.

A worked example

Take a made-up book: Murder at Marigold Bakery, book 2 in the Hollyford Mysteries series, in the category “Cozy Culinary Mysteries”.

“Murder”, “marigold”, “bakery”, “hollyford”, “cozy”, “culinary” and “mystery” are all already covered by the title, series and category. So the seven boxes might be:

1. small english village whodunnit
2. amateur sleuth baker
3. recipes included
4. clean read no swearing
5. retired schoolteacher heroine
6. summer fete scandal
7. lighthearted animal companion

Each box adds something a reader might search for that the rest of the listing doesn’t already say.

Keywords you can change later

Keywords aren’t permanent. You can update them from your KDP Bookshelf at any time, and the change usually shows on Amazon within a few days. If your book isn’t being found, trying new keywords is free and low-risk.

It’s worth a check every few months, especially if you write in a genre where reader trends move quickly.

Doing it before upload day

The best time to choose keywords isn’t at the end of a long upload. It’s while you’re still close to the book, when the setting, characters and themes are fresh in your head.

That’s why Libba has an Amazon tab inside each book. You fill in your seven keyword boxes alongside your manuscript, and Libba checks them as you type. It warns you about words Amazon rejects, words already covered by your title, author, series or categories, and words you’ve repeated across boxes. On upload day, each box has a copy button, so you copy them straight into KDP.

The same tab also holds your book description and a category finder. See How to Choose KDP Categories Using Books Like Yours and How to Write and Format Your Amazon Book Description.

Common questions

Do I have to use all seven boxes? No, but empty boxes are wasted opportunities. If you’re stuck, work through the checklist above.

Can I put the same phrase in my title and my keywords? You can, but it doesn’t help. Your title is already searchable.

Can I use other authors’ names, like “for fans of [author]”? No. Amazon’s guidelines don’t allow other authors’ names or book titles in keywords. Describe the type of book instead, such as “for fans of gothic suspense”.

How quickly will I see results? Keywords help readers find you, but they can’t sell a book on their own. A strong cover, a clear description and good reviews matter just as much.

For the rest of the upload, see How to Format an EPUB for Amazon KDP.