Base64 & Data URI Converter
Convert images to Base64 Data URIs for embedding in HTML, CSS, and emails. Also includes standard text Base64 encode/decode. All processing runs locally in your browser.
💡 Why this exists
AI-generated content often needs to be embedded in HTML, CSS, or Markdown. External image URLs break, get blocked, or require additional HTTP requests. This Capability converts any image to a self-contained Data URI — no external dependencies, no server uploads, works offline.
⚖️ Need to embed images?
- Instant conversion — no upload
- 5 output formats (HTML, CSS, MD, URI, Pure)
- Text encode/decode included
- Zero network calls
- Free, no API key
- Cannot convert images to Base64
- May suggest external services
- No batch processing
- Requires manual steps
- Paid per token
Supports PNG, JPG, SVG, GIF, WebP
Capability Info
| ID | base64.convert |
| Version | 1.0.0 |
| Status | stable |
| Category | Encoding |
| Contract | deterministic, no side effects, local, no AI |
| Runtime | Browser, Node, Edge, Worker |
What is a Data URI?
A Data URI (Uniform Resource Identifier) allows you to embed files directly into HTML and CSS as base64-encoded strings, instead of referencing an external file. This eliminates HTTP requests and is useful for small images, icons, CSS backgrounds, and email templates where external images might be blocked.
Supported Image Formats
- PNG: Best for graphics, logos, images with transparency
- JPG / JPEG: Best for photos and complex images
- SVG: Vector graphics, scales infinitely
- GIF: Animated images and simple graphics
- WebP: Modern format with better compression than PNG/JPG
Output Formats
- Data URI: Full data: URL with MIME type prefix, use anywhere URLs are accepted
- HTML img tag: Ready-to-use <img src="data:..."> tag for embedding in web pages
- CSS background: background-image: url(data:...) for CSS styling
- Markdown:  for Markdown documents
- Pure Base64: Just the base64 string without the data: prefix
When to Use Data URIs
- Small icons and images to reduce HTTP requests
- Email templates where external images get blocked
- CSS sprites and background images
- Single-file HTML documents and tools
- Storing images in JSON or database fields
Considerations
- Base64 encoding increases file size by about 33%
- Best for small images (under 10KB) - larger images should stay as separate files
- Data URIs aren't cached separately like image files
- All processing happens in your browser - images are never uploaded
Frequently Asked Questions
Are my images uploaded to a server?
No. The entire conversion happens in your browser using the FileReader API. Your image files never leave your device.
What's the maximum file size?
There's no hard limit, but very large images will produce very long base64 strings that may slow down your browser. We recommend using Data URIs for smaller images.
Can I convert Base64 back to an image?
Yes, you can paste a Data URI or pure base64 string into most browsers to view the image, or use any base64-to-image tool to decode it.
Frequently Asked Questions
Can I convert images to Base64 in the browser?
Yes. Drop an image file and it is encoded to a Base64 Data URI instantly — useful for embedding small images directly into HTML, CSS or JSON. Nothing is uploaded.
What is the difference between Base64 and encryption?
Base64 is an encoding (reversible, adds ~33% size), not encryption. Anyone can decode it. It is meant for safe transport/storage of binary data, not secrecy.
Does the tool upload my data?
No. Encoding and decoding happen 100% locally. There is no server, no logging, no tracking.
How much larger is Base64 than the original?
Base64 increases size by about 33%: every 3 bytes of input become 4 ASCII characters.
Tools we recommend
Deploy this tool on Vercel · Ship faster with Cursor · Your static site on Cloudflare