Image to Base64 Converter

What is a base64 data URI?

A Base64 data URI packs an entire image's binary data into a text string, prefixed with something like data:image/png;base64,. You can drop that string directly into an HTML <img src> attribute or a CSS background-image instead of linking to a separate image file.

When should I use this?

Embedding small images (icons, logos) as Base64 can reduce the number of separate HTTP requests a page makes, which is useful for tiny assets or email templates where linking external images isn't reliable. For larger images, a regular file with a URL is usually more efficient. Need to go the other direction→ Try our Base64 Encode & Decode tool for text.

The file size tradeoff

Converting an image to Base64 makes it roughly 33% larger than the original file, because Base64 encoding represents every 3 bytes of binary image data as 4 text characters. For a 2 KB icon, that's a negligible difference. For a 500 KB photo, it means embedding nearly 665 KB of text directly into your HTML or CSS file, which can slow down the initial page load since the browser has to download that entire chunk before it can render anything, rather than loading a separate image file that can be cached independently and loaded in parallel with the rest of the page.

How the conversion works

When you drop or select an image, your browser reads the raw file data and encodes it directly using the FileReader API the same browser feature websites use to preview an image before you upload it. The result is a single text string starting with a prefix like data:image/png;base64, that identifies the file type, followed by the encoded image data itself. Because this happens entirely within your browser's memory, the image file itself never leaves your device or touches a server.

Good and bad fits for this technique

Good candidates: small icons, logos, and UI elements that appear on every page load and are unlikely to change, especially in email templates (where external images are often blocked by default) or single-file HTML tools that need to be fully self-contained. Poor candidates: photos, large graphics, or any image over roughly 10-20 KB, where a regular linked image file which the browser can cache and load in parallel with everything else is more efficient.

FAQ

Is my image uploaded anywhere?
No the conversion happens entirely in your browser using JavaScript. Your image is never sent to a server.

Is there a file size limit?
There's no hard limit, but very large images produce very long Base64 strings, which can be slow to work with and aren't a great fit for embedding anyway.

Why is the Base64 output so much longer than my image file?
Base64 encoding turns every 3 bytes of the original image into 4 text characters, making the result about 33% larger than the source file. That's the tradeoff for representing binary image data as plain text.

What image formats does this support?
Any format your browser can read as an image file JPG, PNG, GIF, WebP, and SVG all work, since the conversion uses the browser's built-in file reading, not format-specific processing.

Will embedding an image as Base64 make my page load slower?
For small icons, the difference is negligible. For larger images, yes the browser has to download the entire encoded string before it can render anything, and it loses the ability to cache the image separately from the page, so a regular linked image file is usually better for anything beyond a small icon.

Can I convert multiple images at once?
This tool handles one image at a time. Drop or select a new image to replace the current result, or use Clear to start over before adding the next one.