Base64 File Decoder
Decode Base64 text or a Data URL and download the resulting bytes as a file. Processing takes place locally in your browser.
Start using
What Base64 File Decoder does
Decode Base64 text or a Data URL and download the resulting bytes as a file.
Worked example
Input
Base64 SGVsbG8=; filename hello.txt
Result
A five-byte file containing Hello
How the file is processed
Whitespace and any Data URL prefix are removed, Base64 quartets are decoded to bytes and a local download Blob is created.
Useful workflows
- Prepare test fixtures or inspect supported local files without uploading them.
- Preview filenames, paths and sizes before creating a new download.
- Keep the source file until the generated result opens and validates correctly.
Security and compatibility checks
- Do not open untrusted extracted files; an archive can contain malicious content even when extraction succeeds.
- Browser memory limits make very large files or archives unsuitable for local processing.
- MD5 detects accidental differences but is not secure proof of authenticity; use a modern signed hash workflow when trust matters.
Frequently asked questions
Are files uploaded?
These tools normally read selected files with browser APIs and create local downloads. The page should explicitly disclose any exception.
Why does a generated file not open?
Check the source format, encoding, chunk order, archive support and extension. Renaming a file does not convert its internal format.
Processing takes place locally in your browser.