The Complete Markdown Cheat Sheet (2026 Edition)

Markdown is the universal language for writing on the web. Whether you are drafting a README, writing a blog post, or taking notes, knowing the Markdown syntax by heart saves you time every single day. This cheat sheet covers standard Markdown, GitHub Flavored Markdown (GFM), and the most popular extensions you will encounter in modern editors.

Quick Answer: Markdown uses lightweight symbols to format plain text: **bold**, *italic*, # Heading, `code`, and - list item cover 90% of everyday writing. It powers over 600 million repositories on GitHub, Wikipedia articles, and thousands of documentation sites. Master the 15 core syntax rules in this cheat sheet and you can write formatted documents anywhere.

What Heading Syntax Does Markdown Use?

Use one to six # characters at the start of a line to create headings from H1 to H6.

# Heading 1
## Heading 2
### Heading 3
#### Heading 4
##### Heading 5
###### Heading 6

Most style guides recommend a single H1 per document and avoiding skipping levels (e.g. jumping from H2 to H4). Search engines and screen readers rely on correct heading hierarchy to understand document structure.

How Do You Bold, Italicize, and Format Inline Text in Markdown?

**bold**
*italic*
~~strikethrough~~
==highlight==
`inline code`
~subscript~
^superscript^

Bold and italic can be combined: ***bold italic***. The highlight, subscript, and superscript syntaxes are extensions supported by many editors including edtr.md. Inline formatting is the most-used subset of Markdown, appearing in over 95% of Markdown documents found in open-source repositories.

How Do You Create Links and Images in Markdown?

[Link text](https://example.com)
[Link with title](https://example.com "Title")

![Alt text](image.png)
![Alt text](image.png "Optional title")

For a deeper look at links and images, see the Markdown links guide and the Markdown images guide.

How Do You Create Lists in Markdown?

Unordered Lists

- Item one
- Item two
  - Nested item
  - Another nested

Ordered Lists

1. First
2. Second
3. Third

Task Lists (GFM)

- [x] Completed task
- [ ] Pending task
- [ ] Another pending task

Task lists are part of GitHub Flavored Markdown and are used in millions of GitHub issues, pull requests, and project boards every day. In editors like edtr.md, the checkboxes are interactive. Click to toggle. For a full deep-dive, read the complete guide to Markdown task lists.

How Do You Write Blockquotes in Markdown?

> This is a blockquote.
>
> It can span multiple lines.

Blockquotes are commonly used for pull quotes, callouts, and citing external sources. They nest with additional > characters: >> nested quote.

How Do You Add Code Blocks in Markdown?

Wrap code in triple backticks. Add the language name for syntax highlighting.

```javascript
function greet(name) {
  return `Hello, ${name}!`;
}
```

Most editors support 100+ languages via highlight.js or Prism. edtr.md uses highlight.js with GitHub-style colors. Fenced code blocks are the most common way to share code snippets in technical documentation and README files across GitHub’s 600+ million repositories.

How Do You Create Tables in Markdown?

| Feature   | Supported |
| --------- | --------- |
| Bold      | Yes       |
| Diagrams  | Yes       |
| Math      | Yes       |

Column alignment is controlled with colons: :--- (left), :---: (center), ---: (right). For everything about table formatting, alignment, and edge cases, see the complete Markdown tables guide.

How Do You Add a Horizontal Rule in Markdown?

---
***
___

Any of the three works. Most writers stick with --- for consistency. A horizontal rule creates a thematic break and is rendered as an <hr> element in HTML.

How Do You Write Math Equations in Markdown?

Inline math with single dollar signs, block math with double dollar signs.

Inline: $E = mc^2$

Block:
$$
\int_0^\infty e^{-x^2} dx = \frac{\sqrt{\pi}}{2}
$$

KaTeX supports a large subset of LaTeX and renders client-side in approximately 10ms per equation, making it significantly faster than MathJax for complex documents.

How Do You Embed Mermaid Diagrams in Markdown?

```mermaid
graph LR
  A[Start] --> B[Process]
  B --> C{Decision}
  C -->|Yes| D[Done]
  C -->|No| B
```

Mermaid supports flowcharts, sequence diagrams, Gantt charts, class diagrams, state diagrams, and more, all from plain text. For a complete walkthrough of every diagram type, see the guide to Mermaid diagrams in Markdown.

How Do You Use Callout Blocks in Markdown?

GitHub-style alert syntax for highlighting important information.

> [!NOTE]
> Useful information the reader should know.

> [!WARNING]
> Critical content requiring immediate attention.

> [!TIP]
> Helpful advice for doing things better.

GitHub introduced this callout syntax in 2023. It is now supported by GitHub, edtr.md, and a growing number of documentation platforms. Five types are available: NOTE, TIP, IMPORTANT, WARNING, and CAUTION.

How Do You Add Footnotes in Markdown?

Here is a statement[^1] with a reference.

[^1]: This is the footnote text.

Footnotes are rendered at the bottom of the document with back-links. They are essential for academic writing, legal documents, and any content requiring citations. Both numeric ([^1]) and named ([^name]) references are supported.

How Do You Escape Special Characters in Markdown?

Use a backslash to display literal characters that would otherwise be interpreted as Markdown formatting: \*not italic\* renders as *not italic*.

The characters that must be escaped in Markdown are: \ * _ { } [ ] ( ) # + - . !

Quick Reference Table

Syntax	Result
**bold**	bold
*italic*	italic
~~strike~~	strike
`code`	code
[link](url)	link
	image
$math$	inline math
- [x] task	checked task
> quote	blockquote
---	horizontal rule
[^1]	footnote reference
```lang	fenced code block

Try It Yourself

The best way to learn Markdown is to write it. Open edtr.md and start experimenting. You will see the rendered output in real time, side by side with your source. If you are completely new to Markdown, the Markdown for beginners guide walks you through every concept step by step.