An online markdown editor creates, edits, and previews markdown files directly in a web browser, with nothing to install. The editor renders markdown text into formatted HTML as you type, opens existing .md files as readable documents, and converts HTML, Word, PDF, and plain text into markdown format. Markdown is now the standard writing format on GitHub, Notion, Obsidian, Reddit, and Discord, and a browser-based editor covers the whole workflow: writing, viewing, formatting, and converting.

What Is Markdown?

Markdown is a lightweight markup language that formats plain text using simple symbols. John Gruber and Aaron Swartz created it in 2004, and the core syntax has stayed stable for 22 years. A # makes a heading, double asterisks make bold text, and a hyphen starts a list. In 2026, markdown sits behind documentation, README files, wikis, and notes on GitHub, GitLab, Stack Overflow, Notion, and Obsidian.

Markdown syntax covers 9 core elements:

Raw markdown stays readable on its own, which is the main thing separating it from HTML. A markdown document written in 2004 renders the same way today.

What Is an MD File?

An MD file is a plain-text document saved with the .md or .markdown extension that stores markdown-formatted text. Most md files sit between 1 KB and 100 KB, open in any text editor, and render as formatted documents in a markdown viewer. Software repositories usually carry four of them: README.md, CHANGELOG.md, CONTRIBUTING.md, and LICENSE.md.

The md format keeps structure visible. A Word document buries formatting inside binary XML, while an md file shows every formatting instruction as plain characters. That is why md files work so well in version control, and why they typically come in around 90% smaller than an equivalent .docx.

To open an md file, drag it into the editor or upload it to the viewer below. The rendered document appears in under 1 second.

Online Markdown Editor with Live Preview

The online markdown editor gives you a split-screen workspace: raw markdown on the left, rendered live preview on the right. The preview updates within milliseconds of each keystroke, so the formatted output stays in view while you write. Everything runs in the browser on Chrome, Firefox, Safari, and Edge, and you can start without creating an account.

The editor covers 6 jobs:

1. Write markdown with syntax highlighting and auto-completion for links, lists, and tables.
2. Preview rendered output side by side with markdown live preview.
3. Open existing md files by drag and drop or file upload.
4. Format markdown text with the built-in markdown formatter.
5. Convert HTML, Word, PDF, and text documents into markdown.
6. Export finished documents as .md, .html, or .pdf files.

Writers draft blog posts and READMEs in it; developers keep their documentation in it. Because everything processes locally in the browser, your content stays on your device.

Markdown Viewer: Open and Read MD Files Online

A markdown viewer renders raw md files into formatted, readable documents in the browser. Upload a .md file or paste markdown text, and the md viewer displays headings, tables, links, images, and code blocks exactly as they appear on GitHub. Files up to 10 MB render in under 1 second.

People reach for the md file viewer in a few situations: someone sent them a README.md, they are checking documentation before it ships, or they want to proofread rendered output instead of raw syntax.

The online md viewer follows GitHub Flavored Markdown (GFM), the specification GitHub published in 2017, so tables, task lists, strikethrough, and fenced code blocks display with full fidelity. The viewer is responsive, and an md reader on a phone shows the same rendered result as a desktop browser.

Markdown Live Preview

Markdown live preview shows the rendered HTML beside the raw markdown source and refreshes on every keystroke. There is no write-save-check cycle. A broken table, an unclosed bold marker, or a malformed link becomes visible the moment you type it.

The markdown renderer behind the preview follows the CommonMark specification, first published in 2014, plus GFM extensions for tables and task lists. GitHub uses the same rendering, so a document that looks right in the preview looks right after publishing. Scroll position syncs between the two panes, and the preview stays aligned with the paragraph you are editing.

Markdown Formatter

The markdown formatter standardises spacing, heading hierarchy, list indentation, and table alignment in one click. It applies 5 corrections: heading levels that step down one at a time, uniform list markers, aligned table columns, single blank lines between blocks, and trimmed trailing spaces.

Formatted markdown renders the same as unformatted markdown but is easier to edit and review. Teams that keep documentation in Git run the formatter before committing, because clean markdown produces readable pull-request diffs.

Convert Documents to Markdown

The converter turns 4 input formats into clean markdown: HTML, Word, PDF, and plain text. Each conversion keeps headings, lists, links, tables, and emphasis while stripping format-specific styling. Paste content or upload a file, and the markdown output lands in the editor next to the live preview.

HTML to Markdown

HTML to Markdown conversion maps HTML tags to markdown syntax. An <h1> becomes #, <strong> becomes **, <a href> becomes [title](url), and a <table> becomes a pipe-delimited markdown table. The converter handles nested lists, code blocks, and images, and it strips inline CSS, scripts, and tracking attributes. Web writers use it to move blog posts out of WordPress or Substack and into markdown-based platforms such as Ghost, Hugo, or Astro.

Word to Markdown

Word to Markdown conversion pulls the structure out of a .docx file and rewrites each element in markdown syntax. Headings, bold, italics, both list types, tables, and hyperlinks all carry over. A 20-page Word document converts in under 5 seconds, and embedded images export as separate files with correct markdown image references. Teams moving documentation from Microsoft Word into GitHub wikis or Notion use this conversion to skip the manual reformatting.

PDF to Markdown

PDF to Markdown conversion extracts text, headings, and tables from PDF documents and rebuilds them as editable markdown. The converter reads heading sizes to assign #, ##, and ### levels, straightens multi-column layouts into linear text, and turns detected tables into markdown tables. It suits reports, whitepapers, and any documentation that exists only in fixed layout and needs to become editable again.

Text to Markdown

Text to Markdown conversion applies markdown structure to unformatted plain text. The converter looks for patterns: lines ending in a colon become headings, dash-prefixed lines become lists, and URLs become links. It is a quick way to turn raw phone notes or a transcript into a structured document.

Frequently asked questions

How do I open an MD file?

Drag the file into the markdown viewer above and the rendered document appears instantly in the browser. MD files also open in any plain-text editor, including Notepad, TextEdit, and VS Code, though those show the raw syntax rather than the formatted result.

Is the markdown editor free?

The online markdown editor, viewer, formatter, and all 4 converters are free, with unlimited use. The tools run in the browser on desktop and mobile, and documents process locally on your device.

What is the difference between markdown and HTML?

Markdown is a simplified writing syntax; HTML is the full web markup language that markdown compiles into. Markdown uses 9 core symbols and stays readable as plain text, while HTML uses more than 100 tags and wraps every element in opening and closing brackets. For everyday documents, markdown covers roughly 95% of the formatting with a fraction of the typing.

Can I convert markdown back to HTML, PDF, or Word?

Yes. The editor exports markdown to .html and .pdf directly, and the exported HTML pastes cleanly into Word. Write once in markdown format, then publish in whatever output the destination requires.