Base64 File Encoder and Decoder

Convert files to Base64 and decode Base64 strings back to files. Preview Base64 encoded images directly.

Base64 String

Upload File

About Base64 File Encoder and Decoder

Convert any file to a Base64 string, or decode a Base64 string back into a downloadable file. Base64-encoded files are commonly embedded in JSON APIs, data URIs, CSS, and email attachments.

Images decoded from Base64 can be previewed directly in the tool. All reading, encoding, and decoding happens in your browser — files are never uploaded to a server.

Key Features

  • Encode any file type to a Base64 string
  • Decode Base64 back to a downloadable file
  • Preview Base64-encoded images instantly
  • Local processing — files are never uploaded

Frequently Asked Questions

How do I convert a file to Base64?

Select or drop a file into the tool and it is read locally and converted to a Base64 string you can copy — for example to embed it in JSON or a data URI.

Can I turn a Base64 string back into a file?

Yes. Paste the Base64 string, and the tool decodes it into a file you can download. If the data is an image, you can preview it right in the browser.

Are my files uploaded anywhere?

No. Files are read with the browser’s FileReader API and processed entirely on your device — nothing is sent over the network.

Why is the Base64 version larger than my file?

Base64 represents every 3 bytes as 4 text characters, so the encoded string is about 33% larger than the original file. That is normal and expected.