Base64 Decoder
Decode a Base64 string to UTF-8 text, hex, or another encoding. Invalid input fails with a clear error.
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How to decode Base64
- Paste a Base64 string. Line breaks are ignored.
- Set Output encoding. UTF-8 for text; Hex when the payload is binary.
- Use Standard unless the encoder used a custom alphabet.
- Read the decoded value, or fix the input if the status line reports an error.
Base64 decoding
Inverse of RFC 4648 Base64 and related alphabets
| Accepted input | Standard, URL-safe, and IMAP alphabets; optional whitespace and padding |
|---|---|
| Failure mode | Error status. The page clears output instead of showing a partial decode |
What this decoder does
It reverses Base64 encoding. Standard mode accepts +//, URL-safe -/_, and IMAP's comma. Choose Hex as the output encoding when the bytes are not UTF-8 text.
Fail-safe behavior
If the string is not valid Base64 (wrong length, illegal characters), the output stays empty and the status explains the problem. The decoder will not invent padding in a way that hides a bad alphabet.
Decoder questions
Can I paste Base64 with line breaks?
Yes. Whitespace is stripped before decoding.
What if decoding fails?
You will see an error in the status line. The previous output is cleared so you do not copy a stale result.