Choose Plain text when your source is prose. Blank lines become paragraph breaks, and a single line break inside a paragraph becomes <br>. Choose HTML source when your text already contains markup. The formatter keeps KDP's documented basic tags, removes attributes, unwraps other ordinary tags, and drops scripts and embedded media.
Review the generated HTML, character counts, and change summary. Copy is available through the local 4,000-character boundary. If markup is malformed or the source is too large, correct the original text and format it again. The editor does not change your source while formatting.
Choose a source mode
Plain text never treats angle brackets as markup. The formatter escapes text such as A & B < C so it stays visible in the output. It trims line edges, combines repeated spaces and tabs, and groups nonempty lines into paragraphs.
HTML source is parsed locally without inserting the source into the page. The formatter keeps KDP's documented br, p, b, em, i, u, h4, h5, h6, ol, ul, and li tags. It strips attributes, unwraps unsupported ordinary tags while keeping their text, and drops scripts, styles, embedded content, images, and other media. If supported tags are unbalanced or cross-nested, it asks you to fix the source instead of guessing.
Paragraphs and line breaks
Plain text First line, Second line, a blank line, then Third line becomes <p>First line<br>Second line</p><p>Third line</p>. The preview shows two paragraphs, with a line break inside the first.
Read the output and preview
The generated-source count includes tags and escaped characters. Visible-text count includes the text but not markup. Source overhead is the generated-source count minus the visible-text count. These local counts use Unicode code points; KDP's help does not specify its Unicode counting method.
KDP's book description guidance sets a 4,000-character limit including HTML tags and lists the supported basic tags. The formatter allows copying at a local count of 4,000 or less and withholds it above that count. Check KDP's own counter before saving.
The preview renders only the cleaned, allowlisted structure and cannot guarantee how an Amazon detail page will look. Formatting does not check whether your prose follows KDP's rules for URLs, reviews, promotions, or other description content. Review the saved version in KDP and use the KDP metadata checker for a whole-listing preflight. See also KDP's metadata guidelines.