Most authors don't lose out on discoverability because they picked the wrong keywords; they lose out because they left fields empty, used single words instead of phrases, repeated themselves across fields, or unknowingly used a term Amazon prohibits outright. These are avoidable, mechanical mistakes, and fixing them is often a bigger win than finding the perfect niche keyword.
This is part of the Complete Guide to Amazon KDP Keywords and Categories.
Every unused character in your seven keyword fields is wasted indexing potential. Even a seventh field that feels hard to fill is worth the effort, whether that's a secondary audience identifier, a regional variant, or a less obvious but still accurate descriptor. An empty field helps nothing.
A single word like "mystery" or "romance" generates overwhelming competition, and a new or lesser-known book has essentially no chance of ranking for it. Each field holds up to 50 characters; use that space for a specific, multi-word phrase you can realistically compete for, like "amateur sleuth cozy mystery small town bakery" rather than just "mystery."
Amazon combines all seven fields into a single search index, so using the same word in multiple fields accomplishes nothing beyond the first use. The same applies to words already in your title, subtitle, author name, or series field, all of which are indexed separately. See Backend Keywords vs. Title, Subtitle, and Description Keywords for how these interact.
Amazon reads each field as a continuous string and treats spaces as natural word separators; commas, semicolons, and quotation marks are unnecessary and waste character space you could use for additional search terms. Separate distinct concepts with spaces, not punctuation.
Amazon disallows several categories of keyword content, and using them risks suppression or removal of your listing:
Amazon has described enforcement here as a zero-tolerance policy in some contexts, with consequences ranging from a suppressed listing to account-level action for repeated violations. This isn't a gray area worth testing.
A keyword might have real search volume and reasonable competition, but if it doesn't genuinely describe your book, it will draw readers who bounce off quickly. That hurts your conversion rate, which over time can hurt your ranking more than a lower-traffic but well-matched keyword would have. Relevance matters as much as search volume.
Choosing keywords based purely on what sounds right, without actually searching them on Amazon to see what comes back, means you're flying blind. See How to Do Amazon Keyword Research for Your Book for a process that tests candidate phrases directly against real search results before you commit to them.
Keywords chosen before launch are, at best, educated guesses. Once your book has real sales and search data, revisiting your keywords with that information tends to improve performance meaningfully over the original guess. See How Often Should You Update Your Book's Keywords and Categories?
Need Help Getting This Right?
Entrada Publishing can help you review your book's keywords and categories before you publish.
Amazon can suppress your listing, remove the book, or, for repeated violations, take account-level action. Enforcement in some cases has been described as zero-tolerance.
Yes, in the sense that it's a missed opportunity. An empty field contributes nothing to your discoverability, so it's worth the effort to fill all seven with genuinely relevant phrases.
No. Amazon treats spaces as word separators, and commas waste character space without adding function.
No. Using another author's name or trademark you don't own is prohibited and can result in your listing being suppressed or removed.