Convert Base64 to a File
Decode Base64 back into a downloadable file.
What does Base64 to File Converter do?
Paste a Base64 string or data URI and download it as the original file. The type is detected from the data URI header, or from the decoded content signature when no header is present.
How to Use Base64 to File Converter
- 1Paste your Base64With or without a data URI prefix.
- 2Check the detected typeOverride it if the detection is wrong.
- 3Download the fileWith whatever filename you choose.
Key Features
- Accepts a raw Base64 string or a full data URI
- File type detected from the header or the decoded magic bytes
- Decoded size shown before you download
- Custom filename and extension
- Preview for images, text and PDFs before downloading
- Clear diagnosis for truncated or malformed input
Frequently Asked Questions
How is the file type detected?
From the data URI header if present. Otherwise the decoded bytes are checked against known file signatures — PNG, JPEG, PDF, ZIP and others all begin with a recognisable magic number.
Why does decoding fail?
Usually truncation. Base64 must be a multiple of four characters once padded, and copying from a console or database viewer often cuts the end. Whitespace and line breaks are fine and are stripped.
Is it safe to decode Base64 from an API?
Decoding happens locally so nothing is transmitted. Apply normal caution to the resulting file — a decoded executable from an untrusted source is exactly as dangerous as a downloaded one.
Can I decode a very large string?
Up to a few hundred megabytes on a desktop browser. The whole string must be held in memory, so extremely large payloads can exhaust the tab.
Decoding runs entirely in your browser using the built-in atob function. Nothing you paste is transmitted or logged.
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