Amazon Book Description HTML Formatter

The twelve tags, and the ones that look like they should work

Amazon's description field is not a web page. It renders a fixed, short list of HTML tags and quietly discards everything else: <br>, <p>, <b>, <em>, <i>, <u>, <h4>, <h5>, <h6>, <ol>, <ul>, <li>. That is the entire vocabulary.

The expensive mistakes are the near-misses. <h1>, <h2> and <h3> are not supported, even though <h4> through <h6> are — so the most natural way to write a heading is the one that fails. <div> and <span> do nothing, which matters because they are what a word processor emits. <a> links are stripped, and Amazon separately prohibits linking to other retailers. <img> and <table> do nothing either; a bulleted list is the closest thing the field has to a table.

Nothing tells you when this happens. The description saves, the listing goes live, and the formatting you wrote is simply absent — or worse, printed as visible angle brackets in the middle of your sales copy. The panel above names each tag that would have cost you something and quotes your own markup back at you, because “an unsupported tag was removed” is not something you can act on. Tags that change nothing on Amazon — <div> becoming <p>, the <span> wrappers a word processor leaves behind — are cleaned up quietly, because a list that reports those is a list you learn to scroll past.

Why your description grows blank lines

This is the most common formatting complaint on KDP and the least obvious. The description box treats a line break in your source as content: wherever your HTML has a newline, KDP inserts a <br>. Markup written neatly — one block per line, the way any editor formats it — therefore arrives on the live listing with a phantom blank line between every paragraph, and a preview that looked correct before you pasted.

The standard advice in this corner of publishing is to run your HTML through a minifier before pasting it in. That works, and it is a step nobody should have to know about. The output above is already minified — one continuous line, no breaks for KDP to interpret — so what you paste is exactly what Amazon renders. If you copy your description out of this tool and into an editor that re-indents it, you will reintroduce the problem.

The 4,000-character limit counts your tags

Amazon allows 4,000 characters in a description, and its own help page is explicit that the editor counts every character used including any HTML tags. Most authors budget for the words and are surprised by the markup: wrapping one word in <b></b> costs seven characters on top of the word, a paragraph costs seven, and a seven-item bulleted list costs sixty-eight before a single word of it.

That is why the counter above shows three numbers rather than one: the total KDP will see, how much of it is your text, and how much is formatting. A description that is four hundred characters over the limit is often not too wordy — it is over-formatted, and the fix is to drop a few emphasis tags rather than to cut a paragraph you wanted.

Pasting from Word, Docs, or an old listing

This is the real-world input, and it is messier than it looks. A copy out of Word puts far more on your clipboard than the words: conditional comments aimed at old versions of Internet Explorer, Office-namespaced tags like <o:p>, and Mso class names attached to every paragraph. Google Docs and web pages contribute their own — nested <span> wrappers carrying fonts, sizes and colours that the description field has no way to render.

Pasted into KDP directly, that markup is at best ignored and at worst partially printed. Pasted here, it is stripped on the way in and your bold, italics and lists survive. Because the cleanup runs before the check, the list of changes you see is about your description rather than your word processor.

What Amazon will not accept, tags aside

Valid markup is only half of a description that stays up. Amazon's guidelines also prohibit a set of things about the content: reviews and testimonials, references to your price or to promotions, links or contact details pointing readers elsewhere, requests for reviews, and Unicode emoji. The formatter above flags emoji, since those are unambiguous in the markup, and leaves the judgement calls to you.

If you want the whole listing checked rather than just the description — title length, keyword slots, prohibited claims — the KDP Listing Checker runs the full rule set against the same corpus this page reads, so the two will never disagree about what Amazon supports.

How this tool works

Everything happens in your browser. Your description is parsed into a small document model — headings, paragraphs, lists, and the bold, italic and underline runs inside them — and every panel on the page is rendered from that model. The preview is not your HTML handed to the browser to interpret; it is the same parsed structure drawn as elements, which is why it is safe to paste anything at all in here and why the preview cannot disagree with the markup you copy.

The tag list and the character limit are not typed into this page. They come from the same source module our listing tools read, which records the Amazon help page each rule was written from and the date someone last opened it and confirmed the wording. When that date moves, every page built on it moves with it.