Make chapters reliably detectable
Use styles, hierarchy and Word navigation so visible titles become a dependable book structure.
Read the guide →EPUBIO KNOWLEDGE
Concrete answers for the path to a finished book.
Not a generic SEO blog: epubio Knowledge brings together traceable guidance, tools and production methods for DOCX, EPUB, print and publication.
Published responsibly by epubioEditorial state: 20 August 2026
EPUBIO
From a problem to the next action
Authors rarely search for a technical standard. They want to know why chapters were missed, why an EPUB was rejected or which dimensions a print cover needs.
Each resource should answer a concrete question, state its limits and lead to the right tool or action. Content is dated, assigned to a responsible publisher and reviewed when relevant standards change.
Understand EPUBCheck findings
Interpret errors, warnings and locations, resolve the shared cause and validate the correct book state again.
Understand findings →Calculate a book spine transparently
See how page count, paper and binding connect — and why the printer template remains authoritative.
Understand the calculation →Try, do not just read
Free calculators and simulators explain their method and make effects visible.
Open tools →PRINCIPLES
Editorial principles
Primary sources
Standards and platform requirements are sourced from W3C, EPUBCheck or the relevant provider whenever possible.
No page noise
We do not publish mass variations that merely rephrase the same question.
Practical experience
Product knowledge, real validation workflows and later anonymised findings from approved test cases form the basis.
Visible corrections
Material changes receive a new review state. Old claims are not given a cosmetic new date.
CONTINUE
Start here
Create EPUBFrom manuscript to a technically validated ebook file.DOCX to EPUBWhy controlled import goes beyond simple file conversion.Validate EPUBUnderstand validation results and resolve problems deliberately.Print-ready filesConnect interior, format, spine width and cover.Free toolsEstimate spine width and understand edition changes.ReleaseTwinSee which editions become outdated after a change.