Spec sheets for authors and sellers
The numbers people look up before they publish a book, ship an audiobook or list a product, each with the free tool that applies them. Figures are indicative (October 2026); every page links to the official source.
KDP paperback trim sizes, margins and spine width
Common KDP paperback trim sizes, bleed, inside margins by page count and spine width per page, with a link to a free spine calculator.
OpenEtsy listing limits: title, tags, photos and digital files
Etsy title length, tag count and length, photo size guidance and digital download file limits in one table, with free checkers.
OpenACX audiobook audio requirements
ACX audiobook loudness (RMS), peak, noise floor, sample rate, bit rate and file length limits, with a free file checker.
OpeneBay listing photo requirements
eBay photo minimum size, recommended size, number of photos and file size, with a free photo resizer.
OpenIngramSpark paperback cover specifications
IngramSpark cover bleed, safe area, resolution and spine rules for paperbacks, with a free spine and cover template tool.
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