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File to Base64 Encoder

Encode any file to a Base64 string in your browser. Useful for data URIs, APIs, and email attachments.

File to Base64 converts any file — image, PDF, document, or archive — into a Base64-encoded string. ConvertDa's free File to Base64 tool runs in your browser, so even large files stay private. Copy the result to clipboard or download as a text file.

How to file → base64

  1. 1

    Drop your file into the upload area.

  2. 2

    The Base64 string appears immediately.

  3. 3

    Copy or download it as a text file.

Frequently asked questions

What's the file size limit?

Recommended ceiling is 10MB — Base64 makes the output ~33% larger, and very large strings are slow to copy.

Is the file uploaded anywhere?

No. Encoding is done in your browser via the FileReader API.

How big a file can I encode?

Browser memory is the limit. Files under 100 MB encode reliably on most devices. Encoding inflates file size by about 33%, so a 100 MB file produces a 133 MB string.

Is the encoded output the same on every tool?

Yes. Base64 is a standardized encoding (RFC 4648). Our output matches what any other Base64 tool produces, so you can decode it anywhere.

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