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Sealpaste

File & Image to Base64

Turn an image, PDF or any file into Base64 or a data: URL, ready to paste into HTML, CSS or a JSON request body.

Input type

File

Data URL

How to use it

  1. 1Choose a file (or drop it on the box).
  2. 2Tick "Data URL" to get data:image/png;base64,… for use in src or url().
  3. 3Copy the result or download it as a .txt file.

Private by design

Everything runs in this browser tab. Your input is never uploaded, logged or saved on a server, and there are no public "recent" pages. Close the tab and it's gone.

How we keep it private

Examples

Inline a small icon in CSS

Input

icon.png (1.2 KB)

Output

background-image: url("data:image/png;base64,iVBORw0KGgo…");

When a data URL makes sense

Inlining saves a request for tiny assets like icons in emails or single-file HTML. Base64 is about 33% larger than the file itself, so for anything over a few kilobytes a normal file is usually faster.

APIs that accept files in JSON (for example document or image uploads) often want plain Base64 without the data: prefix; leave "Data URL" off for those.

Frequently asked questions

Is there a file size limit?

Files up to 10 MB work comfortably. The file is read from your disk by the browser; it never goes over the network.

Is my data or file uploaded?

No. Encoding and decoding happen in your browser, including files. Nothing is sent to a server.