BMP to Base64 Converter
Convert a BMP image to a Base64-encoded string. Upload a BMP file and get a data URI you can embed directly in HTML, CSS, or JSON.
Click to upload a BMP image
Your file is processed entirely in your browser
Recommended Settings
Pro Tips
- •Base64 encoding increases the data size by roughly 33%, so embedded images should generally stay small
- •Include the data URI prefix when embedding directly in HTML or CSS with url(...) or src="..."
- •Omit the prefix if you're inserting the string into a field that already specifies its own MIME type
- •The whole file is encoded locally in your browser - nothing is uploaded anywhere
Most Popular
Most users keep the data URI prefix so the string can be pasted directly into an <img> src or CSS background-image
When to Use This Tool
Embed a small BMP image directly in HTML, CSS, or JavaScript without needing a separate file request.
Include image data inline in a JSON API request or response where a separate file upload isn't practical.
Embed small images directly in email HTML using a Base64 data URI instead of linking to an external image.
Bundle an image into a single self-contained HTML or config file with no external dependencies.
How It Works
Read the uploaded BMP file directly as raw bytes in your browser
Encode those bytes into a Base64 data URI using the browser's native FileReader API
Optionally strip the data URI prefix, leaving just the raw Base64 string
Display the result, ready to copy or download
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Browser native FileReader API for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
What is a data URI?
A data URI embeds a file's content directly in a string, prefixed with its MIME type, like "data:image/png;base64,...". It can be used anywhere a URL is expected, such as an <img> src attribute or a CSS background-image.
Why does the Base64 string look so much longer than my file?
Base64 encoding represents every 3 bytes of binary data as 4 ASCII characters, which increases the size by about 33% compared to the original file.
Should I include the data URI prefix?
Include it if you're pasting the string directly into an <img> tag, CSS, or anywhere a full data URI is expected. Omit it if you're inserting the raw Base64 into a field, like a JSON property, that already tracks the MIME type separately.
Is my image uploaded to a server?
No. The entire file is read and encoded locally in your browser using the FileReader API. Your image never leaves your device.
Is there a size limit?
The tool works entirely in your browser, so practical limits depend on your device's memory. Base64 encoding is best suited for small to medium-sized images - very large files may cause performance issues in downstream applications.