How these checks work
These checks are SmartKDP's reading of Amazon's published KDP help pages, not an Amazon-verified result. A clean report means our rules found nothing — KDP reviews listings on more than metadata, so it is not approval, and Amazon can change its guidelines at any time. Every finding links the help page it came from and the date we last checked it.
Where the rules come from
We wrote every rule ourselves by reading Amazon's public KDP help pages. Nothing here is copied from another tool's constants or word lists. Each source below is re-read periodically, and the date is what we show beside a finding — Amazon revises these pages without announcing it, so a date that has drifted is something you should be able to see rather than something we hide.
- Metadata Guidelines for Books · last checked 2026-08-04
- Make Your Book More Discoverable with Keywords · last checked 2026-08-04
- Write a Book Description · last checked 2026-08-04
- A+ Content Guidelines · last checked 2026-09-05
What this tool deliberately does not check
Two of Amazon's own prohibitions are not implemented, and saying so is more useful than a silence you could mistake for coverage.
- Trademarked terms.Amazon prohibits “unauthorized reference to a trademarked term”, but answering that needs a search of the trademark register rather than a word list. Our Book Trademark Checker does that job.
- Spoilers. Prohibited in descriptions, and not detectable by any rule we could write honestly.
- Everything outside your metadata.Manuscript content, cover art, category fit, and pricing are all part of KDP's review and none of them are visible to this tool.
Published limits 3
Numeric caps Amazon states outright. We can quote the figure, and the tool shows a live counter for each one.
| Rule | Applies to | Why | Source |
|---|---|---|---|
Title and subtitle lengthlimit.title-subtitle-length | Title, Subtitle | Amazon requires the title and subtitle together to be fewer than 200 characters. Over the cap the listing is refused at submission rather than trimmed for you. | Metadata Guidelines for Books (2026-08-04) |
Description lengthlimit.description-length | Description | The description field holds 4,000 characters, and KDP's counter includes any HTML tags you use — bolding one word costs seven characters on top of the word itself. | Write a Book Description (2026-08-04) |
Keyword slot countlimit.keyword-slot-count | Keywords | KDP gives you seven keyword boxes. Anything past the seventh has nowhere to go. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Prohibited content 20
Content Amazon's guidelines explicitly forbid. Each rule below links the page carrying the prohibition.
| Rule | Applies to | Why | Source |
|---|---|---|---|
Sales-rank claimsprohibited.sales-rank-claim | Title, Subtitle, Keywords | Listed verbatim among the things a title may not contain: "Reference to sales rank (e.g., 'bestselling')". It applies whether or not the claim is true, and the keyword page repeats it. | Metadata Guidelines for Books (2026-08-04) |
Promotional claimsprohibited.promo-claim | Title, Subtitle, Keywords | Listed verbatim: "Reference to advertisements or promotions (e.g., 'free')". These phrases are unambiguous promotions — the ambiguous single words are handled separately so a gluten-free cookbook is not accused of advertising. | Metadata Guidelines for Books (2026-08-04) |
Ambiguous promotional wordsprohibited.promo-word | Title, Subtitle, Keywords | The same prohibition as above, but on single words that have an innocent reading — "free" in "gluten-free", "sale" in "Garage Sale Mystery". A warning rather than an error, because only you know which sense you meant. | Metadata Guidelines for Books (2026-08-04) |
Time-sensitive statementsprohibited.time-sensitive | Title, Subtitle, Keywords | The keyword page names "Time-sensitive statements ('new,' 'on sale,' 'available now')" among the terms to avoid. A listing outlives the moment it was written. The description carries the same prohibition from a different page, so it is a separate rule below. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Time-sensitive information in the descriptionprohibited.time-sensitive-description | Description | The description guidelines prohibit "Time-sensitive information". A description outlives the promotion that prompted it, and Amazon does not date-stamp it for the reader. | Write a Book Description (2026-08-04) |
Subjective quality claims in keywordsprohibited.subjective-quality-keyword | Keywords | The keyword page says to avoid "Subjective claims about quality (e.g. 'best novel ever')". Scoped to keywords deliberately — this prohibition is not stated for titles, and plenty of legitimate low-content titles say "Perfect Gift". | Make Your Book More Discoverable with Keywords (2026-08-04) |
HTML tags outside the descriptionprohibited.html-in-metadata | Title, Subtitle, Keywords | Both the metadata and keyword pages list "HTML tags" as prohibited. Only the description renders HTML — anywhere else the markup shows up literally on your product page. | Metadata Guidelines for Books (2026-08-04) |
Contact details in the descriptionprohibited.contact-info | Description | Prohibited verbatim: "Phone numbers, physical mail addresses, email addresses, or website URLs". Amazon does not want the description routing buyers off Amazon. | Write a Book Description (2026-08-04) |
Reviews and review requestsprohibited.reviews-testimonials | Description | Prohibited verbatim: "Reviews, quotes, or testimonials" and "Requests for customer reviews". Amazon reserves review content for the review section. | Write a Book Description (2026-08-04) |
Price, availability, and ordering informationprohibited.price-availability | Description | Prohibited verbatim: "Availability, price, alternative ordering information". A price in the description goes stale the first time you change it, and pointing buyers elsewhere is what the rule is really aimed at. | Write a Book Description (2026-08-04) |
Emoji in the descriptionprohibited.emoji-in-description | Description | The description guidelines list "Unicode emojis" among prohibited content. | Write a Book Description (2026-08-04) |
Punctuation-only fieldsprohibited.punctuation-only | Title, Subtitle | Listed verbatim among prohibited title content: "Only Punctuation (e.g. '!!!!!!!!')". Stated for the title and subtitle only — we do not extend it to keyword boxes, where Amazon says nothing about it. | Metadata Guidelines for Books (2026-08-04) |
Placeholder valuesprohibited.placeholder-value | Title, Subtitle | Listed verbatim: "Using only 'unknown,' 'n/a,' 'na,' 'blank,' 'none,' 'null,' 'not applicable'". A field you have nothing for should be left empty, not filled with a word meaning empty. Stated for the title and subtitle only. | Metadata Guidelines for Books (2026-08-04) |
Amazon program names in keywordsprohibited.amazon-program-name | Keywords | The keyword page names "Amazon program names like 'Kindle Unlimited' or 'KDP Select'" as terms to avoid. They describe how the book is distributed, not what it is about. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Quotation marks in keywordsprohibited.quotation-marks-in-keywords | Keywords | The keyword page tells you to avoid "Quotation marks in search terms". Quoting a phrase narrows the match rather than widening it, so the box matches fewer shoppers, not more. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Generic category terms as keywordsprohibited.generic-keyword-slot | Keywords | The keyword page says to avoid "Common category terms like 'book'". A box spent on "book" is a box not spent on something a shopper actually types. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Repeated generic words in the titleprohibited.repeated-generic-term | Title, Subtitle | Listed verbatim among prohibited title content: "Repeating generic keywords like 'notebook,' 'journal,' 'gifts,' 'books,' etc." Using one once is fine; repeating it is the stuffing pattern the rule targets. | Metadata Guidelines for Books (2026-08-04) |
Keywords repeating the titleprohibited.keyword-repeats-title | Keywords | The first item on the keyword page's avoid-list is "Information already in title, contributors, or other metadata" — Amazon already indexes your title, so a keyword box repeating it buys nothing. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Unsupported HTML tagshtml.unsupported-tag | Description | KDP renders exactly twelve tags in a description: <br>, <p>, <b>, <em>, <i>, <u>, <h4>, <h5>, <h6>, <ol>, <ul>, <li>. Anything else — including <h1> through <h3>, which look like they ought to work — is stripped or printed literally. | Write a Book Description (2026-08-04) |
Unbalanced HTML tagshtml.unclosed-tag | Description | An unclosed tag runs to the end of the description, so one missing </b> bolds everything after it. KDP does not repair this for you. | Write a Book Description (2026-08-04) |
Our suggestions 8
Amazon has published no rule on any of these. They are our judgment about what makes a listing work, and the tool labels them as ours wherever they appear.
| Rule | Applies to | Why | Source |
|---|---|---|---|
Keyword box lengthheuristic.keyword-slot-bytes | Keywords | Amazon's keyword page says only to "keep an eye on the character limit in the text field" and never publishes a number. 50 bytes is the cap observed in KDP's own form, so this is our measurement rather than Amazon's rule — and it is bytes, not characters, so accented and non-Latin words fill a box far sooner. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Words repeated across keyword boxesheuristic.keyword-duplicate-across-slots | Keywords | Amazon combines your seven boxes when it matches a search, so the same word in three boxes is matched once and two boxes are wasted. Amazon states the combining behaviour but draws no conclusion — the advice is ours. | SmartKDP judgment — no Amazon rule |
Words repeated inside one keyword boxheuristic.keyword-duplicate-within-slot | Keywords | A word twice in the same box is almost always a typo or a copy-paste, and it spends bytes against the box's size for nothing. | SmartKDP judgment — no Amazon rule |
Repeated words in the titleheuristic.title-stuffing | Title, Subtitle | A word three or more times across a title and subtitle reads as search-engine bait to a shopper, whatever Amazon's systems make of it. Generic words are covered by Amazon's own rule and are excluded here so the same problem isn't reported twice. | SmartKDP judgment — no Amazon rule |
Repeated words in the descriptionheuristic.description-stuffing | Description | Both an absolute count and a share of the text have to be exceeded before this fires. A long description repeats its subject naturally, and flagging that would make the check noise. | SmartKDP judgment — no Amazon rule |
Shouted textheuristic.all-caps | Title, Subtitle, Description | Amazon does not prohibit capitals, but a run of them reads as shouting and is harder to scan. Three consecutive fully-capitalised words is the trigger, so an acronym or a stylised single word passes. | SmartKDP judgment — no Amazon rule |
Over-long keyword phrasesheuristic.long-keyword-phrase | Keywords | Amazon notes that single words tend to work better than phrases. A box of seven or more words is closer to a sentence than to anything a shopper types. | Make Your Book More Discoverable with Keywords (2026-08-04) |
Emoji and symbols in the titleheuristic.title-emoji | Title, Subtitle | Amazon prohibits emoji in descriptions but says nothing about titles. They render inconsistently across the store, the app, and print, and they are not searchable — so this is our recommendation, not a rule. | SmartKDP judgment — no Amazon rule |
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