Markdown to AsciiDoc Converter

How to use

1. 1Pick the direction: Markdown to AsciiDoc to migrate Markdown into an .adoc file or Antora module, or AsciiDoc to Markdown to pull an Asciidoctor section back out into Markdown.
2. 2Paste your text into the left panel, or click one of the sample buttons to load a typical README, tutorial, or release notes layout.
3. 3Read the converted output on the right and use the syntax cheat sheet card below for any rule you want to double-check.
4. 4Click Copy to copy the result to your clipboard, then paste it into your .adoc file, Antora content folder, GitHub README, or Markdown editor.
5. 5Use Swap output into input to chain a round trip and confirm the conversion is lossless for your content.

About this tool

Markdown to AsciiDoc Converter rewrites CommonMark and GitHub-Flavored Markdown into AsciiDoc, the lightweight markup used by Asciidoctor, Antora, GitHub (.adoc files render natively), Maven and Gradle generated sites, OpenStack docs, and most modern dev documentation toolchains. It also runs in reverse so you can pull an existing .adoc file into Markdown for a README, GitHub issue, Linear ticket, or notes app, and put it back. Every construct is mapped: ATX and setext headings become = through ====== with a leading space, bold (**text** or __text__) becomes AsciiDoc's single-asterisk bold (*text*), italic becomes _text_, strikethrough becomes [.line-through]#text# using the built-in role span (AsciiDoc has no tilde syntax), inline code stays as single backticks but switches to the `+...+` passthrough form whenever the content contains a backtick, fenced code blocks become an [source,lang] attribute followed by a four-dash listing delimiter with the language hint preserved (or a plain listing when no language is given), links become url[label] for external URLs (autolink shorthand when the label matches the URL) and link:path[label] for relative paths, bare URLs pass through unchanged, images on their own line become block-level image::url[alt] macros while inline images become image:url[alt], blockquotes wrap in [quote] / ____ delimited blocks, horizontal rules become ''', ordered lists use . per level (up to five levels), unordered lists use * per level, GFM tables become |=== fenced tables with one cell per pipe, and cross-references like [anchor](#anchor) become <<anchor,label>> so internal navigation survives the round trip. Reference-style Markdown links are resolved inline since AsciiDoc has no reference syntax. The reverse direction reads [source,lang] / ---- listings back as fenced code, ---- and .... delimited blocks as plain code blocks, [quote] / ____ as Markdown blockquotes, |=== tables as GFM tables, role spans [.line-through]#text# as ~~text~~, and Asciidoctor link, mailto, and image macros as Markdown links and images. A built-in side-by-side syntax cheat sheet keeps every rule visible while you edit. Three Markdown samples cover the most common documentation shapes: a README with a CI badge and usage table, a tutorial with code blocks and ordered steps, and release notes with breaking changes and a benchmark table. The conversion is deterministic and runs entirely in your browser using a hand-written line-by-line parser with a token-protection pass so emphasis cannot double-process the contents of links, images, or code spans. Useful when migrating a Markdown docs set to Antora, copying README content into an Asciidoctor page, pulling an Asciidoctor section out for a GitHub issue, or porting between toolchains during a tech-writer handoff. Nothing is uploaded, so private documentation stays on your device.

Free to use. Works in your browser. No signup, no login.