Decode from Base64
Instantly decode Base64 strings or files back to their original format, right in your browser.
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Invalid Base64 input. Please check your data and try again.
Decode a file from Base64
Drop your Base64 file here, or click to browse
Do not execute decoded files from untrusted sources.
What is Base64 decoding?
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Security & Privacy
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How Base64 works
Frequently Asked Questions
What is Base64 decoding?
Base64 decoding is the reverse of encoding — it converts a Base64 string back to its original binary or text data. Used to recover data from JWT tokens, email attachments (MIME), API responses, and data URIs.
Is Base64 decoding the same as decryption?
No. Base64 is encoding, not encryption. Anyone can decode a Base64 string instantly — there is no key or password required. Never use Base64 alone to protect sensitive data.
What does "Invalid Base64 input" mean?
The input contains characters outside the Base64 alphabet (A–Z, a–z, 0–9, +, /, =). Common causes: extra whitespace, missing = padding, or the URL-safe variant (- and _ instead of + and /).
How do I decode a Base64URL string?
Base64URL replaces + with - and / with _ and removes = padding. Before decoding, replace - with +, _ with /, and add missing = padding so the length is a multiple of 4.
Can I decode binary files like images or PDFs?
Yes. Use the file decode section to upload a Base64-encoded .txt file. The tool decodes the binary content and offers it as a download with the correct file type detected automatically.