Is my image uploaded to a server?

No. The entire encoding process runs inside your browser using the FileReader API. Your image never leaves your device.

What image formats are supported?

Any format your browser can read: PNG, JPEG, GIF, WebP, SVG, BMP, ICO, and more. The MIME type is detected automatically from the file.

Why is the Base64 string so long?

Base64 encoding expands binary data by roughly 33%. A 100 KB image becomes approximately 133 KB of text. This is normal and expected.

When should I use a data URI vs. a separate image file?

Data URIs are best for small images (under ~5 KB) or when you need a completely self-contained file. Larger images are better served as separate files for caching and performance reasons.

Can I use the output directly in CSS?

Yes. Select the "CSS snippet" output format and paste it into your stylesheet as background-image: url("data:...").

Base64 Image Encoder

Upload an image and instantly get its Base64-encoded data URI for embedding in HTML or CSS.

Upload Image

Click or drag an image here PNG, JPEG, GIF, WebP, SVG, BMP…

Output Format

Full data URI data:image/png;base64,… Base64 string only HTML <img src="…"> CSS background-image: url(…)

Upload an image to see the Base64 output

Summary

Base64 Image Encoder converts image files to Base64-encoded data URIs entirely in your browser — no file is ever uploaded to a server. The resulting string can be pasted directly into an HTML img src attribute or a CSS background-image property to embed images without an extra HTTP request. It works with PNG, JPEG, GIF, WebP, SVG, and other common image formats.

How it works

Click "Choose Image" or drag and drop an image file onto the upload area.
The tool reads the file using the browser FileReader API and encodes it to Base64.
A live preview of the image appears alongside the generated data URI string.
Select the output format you need: full data URI, Base64-only string, or an HTML/CSS snippet.
Click "Copy" to copy the output to your clipboard, ready to paste into your code.

Use cases

Embed small icons or logos in HTML emails where external images may be blocked.
Include images inline in a single-file HTML document or web app.
Set CSS background images via a data URI to avoid an extra HTTP request.
Store small images as strings inside JSON configuration or data files.
Test image rendering in environments that block external URLs.
Bundle assets into a self-contained HTML prototype for sharing.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu