The Ultimate Markdown Cheat Sheet & Syntax Guide
Markdown is the universal formatting standard for developers, technical writers, and AI prompt engineers. Whether you are crafting a README.md for GitHub, writing documentation, or structuring prompts for Claude and ChatGPT, use this quick cheat sheet to copy exact syntax and preview the visual output.
1. Basic Text Formatting
| Element | Markdown Syntax | Rendered Output |
|---|---|---|
| Heading 1 | # Heading 1 | Heading 1 |
| Heading 2 | ## Heading 2 | Heading 2 |
| Heading 3 | ### Heading 3 | Heading 3 |
| Bold | **bold text** | bold text |
| Italic | *italicized text* | italicized text |
| Bold & Italic | ***bold italic text*** | bold italic text |
| Strikethrough | ~~strikethrough~~ | strikethrough |
| Blockquote | > Quote message | Quote message |
| Horizontal Rule | --- |
2. Tables (GitHub Flavored Markdown)
Align columns using colons in the header separator row: :--- for left-aligned, :---: for centered, and ---: for right-aligned.
| Feature | Type | Speed |
| :------------- | :---------: | -------: |
| Real-time GFM | Client-Side | < 1ms |
| Data Privacy | 100% Local | Zero API |
| File Export | HTML & MD | Instant || Feature (Left) | Type (Center) | Speed (Right) |
|---|---|---|
| Real-time GFM | Client-Side | < 1ms |
| Data Privacy | 100% Local | Zero API |
3. Lists & Task Checklists
| List Type | Markdown Syntax | Notes |
|---|---|---|
| Unordered List | - Item A | Use - or *. Indent with 2 spaces for nested bullets. |
| Ordered List | 1. First | Numbers do not need to be sequential; parser handles ordering automatically. |
| Task Checklist | - [ ] Pending task | Renders interactive checkboxes on GitHub and supported markdown renderers. |
4. Code Blocks & Syntax Highlighting
Wrap code or terminal keywords with single backticks: `npm run build` renders as npm run build.
```typescript
function greet(name: string): string {
return `Hello, ${name}!`;
}
```5. GitHub Alerts & Callouts
GitHub supports 5 distinct alert callouts in markdown files using blockquote tags:
Useful information that users should know.
Helpful advice for doing things better or easier.
Crucial information needed for users to succeed.
Urgent info that needs immediate user attention.
Advises about risks or negative outcomes of certain actions.
Frequently Asked Questions
Where can I find a complete Markdown cheat sheet with live preview?
RunOfflineTools provides an all-in-one Markdown Cheat Sheet and real-time live preview editor. It covers basic CommonMark syntax, GitHub Flavored Markdown (GFM) tables, checklists, code blocks, and GitHub alerts with 100% private, client-side browser execution.
How do I create a table using this Markdown cheat sheet?
Create tables using pipes (|) to separate columns and hyphens (-) for header dividers. Control text alignment with colons: left-align (:---), center-align (:---:), and right-align (---:). Click the 'π Table' quick-insert button above the editor to insert a pre-formatted template instantly.
How do task lists and checklists work in Markdown?
Use '- [ ] Item' for an unchecked task and '- [x] Item' for a completed task. GitHub, GitLab, and our live previewer render them as interactive or styled checkable boxes.
How do I format code blocks with syntax highlighting?
Wrap your code in triple backticks (```) and specify the language immediately after the first backticks (e.g., ```javascript or ```python). Our editor highlights syntax cleanly in both rendered preview and raw HTML exports.
How do GitHub alerts (> [!NOTE]) work in Markdown?
GitHub alerts use blockquotes with an alert identifier tag: > [!NOTE], > [!TIP], > [!IMPORTANT], > [!WARNING], or > [!CAUTION]. Follow the tag with your callout text to render formatted notice banners in Git documentation.
Can I export my Markdown to raw HTML or copy it with one click?
Yes! Click the '</> HTML' button or switch to the Raw HTML preview tab to copy fully rendered HTML code, or click 'Copy MD' to copy your raw formatted Markdown for Git READMEs and blogs.
Does this Markdown cheat sheet and editor work offline?
Yes. All parsing and real-time rendering execute 100% locally inside your browser's JavaScript runtime with zero external server requests.