Image to Base64
Convert an image to a Base64 data URI for embedding in HTML or CSS.
The image to Base64 tool gives you the matching Base64 data URI as soon as you upload an image, with one-click copy of the string or a ready-made CSS background-image snippet. Embedding small icons directly in HTML, CSS, or config files removes an extra image request. All conversion runs locally in your browser and images are never uploaded.
Tool area
Worked example: output size and data URI format for a small icon
After uploading a roughly 20KB PNG icon, the "Base64 length" field shows a character count that typically lands around 4/3 of the original byte size. Compare it directly with the "Original file size" field to confirm whether the roughly 33% expansion actually holds.
The output data URI always starts with data:image/png;base64, (or image/jpeg, image/webp, and so on, matching the source file). The tool does not convert formats, so if a format change is needed first, run the file through this site's image format converter before coming here.
- Click "Copy" for the full data:image/...;base64,... string, ready to paste into an img tag's src attribute.
- Click "Copy as CSS" for the full line background-image: url("data:image/...;base64,..."); ready to paste into a CSS file.
What happens past 5MB, and how to verify the output actually works
A file over 5MB is rejected the instant it is selected, showing "The image is too large (about 5MB max); please choose a smaller file." It does not attempt a partial read or compress-then-convert; nothing is sent to a server, and everything happens inside the browser tab.
To verify the output works, paste the "Copy as CSS" result into a test HTML file's style attribute and open it in a browser to confirm the image displays. You can also paste the full string into a new browser tab's address bar to preview it directly and confirm nothing was truncated.
This tool suits small icons, logos, or simple graphics in the range of a few KB to a few hundred KB. A large photo converted to Base64 produces an extremely long string, and embedding that in CSS or HTML makes the file hard to maintain — a regular image file referenced by path is the better choice in that case.
How to use
- Choose the image file to convert (5MB or less recommended).
- The Base64 data URI is generated instantly.
- Click "Copy" for the string, or "Copy as CSS" for a background-image snippet.
- Paste the string into your HTML, CSS, or config file.
Use cases
- Embed a small icon in CSS to remove an extra request.
- Put an image directly in HTML when there is no image host.
- Embed an image in a config file or email template.
Who is it for
- Front-end developers embedding small icons in HTML or CSS
- Users without image hosting who need to embed an image directly
- Marketing and engineering staff embedding images in email templates or config files
Real examples
Embed a logo directly in CSS
Upload a PNG logo of a few dozen KB, click "Copy as CSS" to get the full background-image line, and paste it into a stylesheet to remove one extra image request. Confirm the file is under 5MB before uploading.
Embed a small image in an email template
Some email systems make external image links inconvenient, so a small icon can be converted to a Base64 data URI and written directly into the HTML. The string makes the template source much longer, so this only suits small icons.
Good to know
- The file-size ceiling is hard-coded at exactly 5 x 1024 x 1024 bytes (about 5MB), and larger files are rejected the moment they are selected.
- The tool does not convert image formats; the output MIME type always matches the original uploaded file.
- The Base64 string is typically about a third larger than the original file, so large photos are not a good fit for this kind of embedding.
FAQ
- Does Base64 make the file bigger?
- Yes, the encoded string is usually about 33% larger than the original, so use it for small icons.
- Is my image uploaded?
- No, all conversion happens locally in your browser.
- Why is there a size limit?
- Large images produce very long strings and use a lot of memory, so a ~5MB limit keeps it responsive.
- Can I use it directly in an HTML image tag with alt text?
- Yes, put the data URI in the image tag src and add descriptive alt text to display the image.
- Which formats are supported?
- Common formats like JPG, PNG, WebP, GIF, and SVG are supported.
Privacy & local processing
🔒 This tool runs entirely in your browser. No data is uploaded to any server.
Image to Base64 runs entirely in your browser; no files are uploaded.
Trust & usage note
This tool runs mainly in your browser. Your input is not actively uploaded to a server. Avoid entering highly sensitive data. Results are for reference only.
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