Free online ASCIIDOC to DOCBOOK converter

What the ASCIIDOC format is

AsciiDoc is a plain-text markup format for technical documentation, manuals, README files, books, and web documentation. Authors write readable source files with extensions such as .adoc or .asciidoc, using conventions for headings, lists, admonitions, tables, links, images, source code, attributes, and includes.

The primary software used to create and process AsciiDoc documents is Asciidoctor, a Ruby-based converter with implementations for other runtimes. The older asciidoc processor also supports the format. You encounter these files in software repositories, documentation projects, static-site workflows, and source packages.

What the DOCBOOK format is

DocBook is an XML vocabulary for structured books, manuals, articles, reference pages, and other technical publications. A DocBook file stores semantic elements such as <section>, <para>, <itemizedlist>, <programlisting>, and <figure> rather than presentation-specific formatting.

DocBook is useful when an XML publishing tool, content-management system, validation process, or archival workflow requires a standardized source format. DocBook output can be transformed with tools such as publican, dblatex, FOP, or XSLT stylesheets. DocBook 5 uses XML namespaces and a modern schema; older workflows may require DocBook 4 output.

How to convert ASCIIDOC to DOCBOOK

Asciidoctor provides the most direct conversion. Install it through RubyGems, then run:

gem install asciidoctor
asciidoctor -b docbook5 -o manual.xml manual.adoc

The -b docbook5 option selects DocBook 5 output, -o manual.xml sets the destination filename, and manual.adoc is the source file. To write the result beside the source with an automatically derived name, use:

asciidoctor -b docbook5 manual.adoc

For a complete project whose source includes other files, run the command from the project directory and check that relative include paths and image paths are correct. Asciidoctor resolves included files during conversion, so missing files can produce errors or incomplete output. Attributes can be supplied on the command line, for example:

asciidoctor -b docbook5 -a toc -a source-highlighter=highlight.js -o manual.xml manual.adoc

Use -b docbook4 only when the receiving application cannot process DocBook 5:

asciidoctor -b docbook4 -o manual.xml manual.adoc

For a no-install conversion, the built-in converter on 101convert.com can convert the file for free. Download the resulting XML and inspect it before importing it into a publishing workflow.

Quality and compatibility considerations

The output is a structural conversion, not a visual copy of a rendered document. AsciiDoc attributes, custom roles, extensions, macros, embedded HTML, diagrams, and unsupported block types may require manual adjustment or an Asciidoctor extension. Images are normally referenced by path rather than embedded in the XML, so copy the image directory and preserve the relative locations expected by the DocBook processor.

Validate the result against the schema required by the next tool. DocBook 5 documents use a namespace, while DocBook 4 documents use a different declaration and element conventions. Also verify code listings, tables, admonitions, cross-references, footnotes, and included files because backend-specific behavior can differ from the original AsciiDoc rendering.