Encoded header
Paste a header value or full header lines.
Tip: press Ctrl+Enter (or Cmd+Enter) to decode.
Private browser tool
Free RFC 2047 MIME Header Decoder
An RFC 2047 MIME header decoder converts encoded words such as =?UTF-8?B?...?= in email Subject, From, and other headers back into readable Unicode text. Paste a raw header below to decode Base64 and quoted-printable words instantly.
Private by design: decoding happens in your browser. Header content is never sent to a server.
Decoded text
Readable Unicode with ordinary text preserved.
Encoded words
0
Decoded
0
Kept as is
0
How to decode a MIME encoded header
- 1
Paste the header
Paste a Subject or From value, or several full header lines copied from a raw email. Folded lines are fine.
- 2
Decode
Select Decode or press Ctrl+Enter. Base64 and quoted-printable encoded words are converted to readable Unicode text.
- 3
Review and copy
Check the per-word breakdown and any warnings, then copy the decoded header for your notes, tickets, or code.
Frequently asked questions
What is an RFC 2047 encoded word?
An encoded word is a header fragment in the form =?charset?B?text?= or =?charset?Q?text?=. Mail clients use it to carry non-ASCII text, such as accented names or emoji, in headers that must stay ASCII.
What is the difference between B and Q encoding?
B encoding stores the bytes as Base64. Q encoding is a quoted-printable variant where =XX is a hexadecimal byte and an underscore stands for a space. Both are decoded to bytes and then read with the declared charset.
Why does the space between two encoded words disappear?
RFC 2047 says whitespace between two adjacent encoded words is ignored. Senders split long text across several words, so the decoder joins them back together. Whitespace next to ordinary text is kept.
Is my header content sent to MailParse?
No. Decoding runs entirely in your browser with the built-in TextDecoder API. Nothing you paste is uploaded, logged, or stored.
What happens with malformed or unsupported encoded words?
The decoder keeps the original text in the output and lists a warning that explains the problem, such as invalid Base64, a bad hexadecimal escape, or a charset your browser cannot decode.