How to decode a UTF-8 email subject (Base64 and Q)

Read the format

An encoded word contains a charset, an encoding marker and encoded text. B means Base64; Q is the header-specific Q encoding. This example decodes to Cafe with an accented e.

=?UTF-8?B?Q2Fmw6k=?=

Decode the subject

Copy the encoded subject value into the email header decoder. SpamBite supports UTF-8 B and Q encoded words, including folded headers. Malformed input and unsupported encodings can fail; keep an untouched copy of the source.

Check these small details

An underscore in a Q encoded word represents a space, not a literal underscore. A folded continuation starts with whitespace. Adjacent encoded words can be joined without adding the folding whitespace to the decoded text. Keep the charset and closing ?= intact.

Q encoding:
=?UTF-8?Q?Caf=C3=A9_today?=
Decoded: Café today

Folded encoded words:
=?UTF-8?B?Q2Fmw6k=?=
 =?UTF-8?B?IHRvZGF5?=
Decoded: Café today

Use the right field

Most campaign editors expect normal readable subject text and handle encoding themselves. Only use an encoded header when working with raw email source or a system that explicitly expects RFC 2047 syntax.

Encoding is not a spam workaround

Email clients and filtering systems can decode encoded headers. Encoding is a way to represent text, not a way to hide promotional claims or guarantee inbox delivery. Unicode styling can also make subjects less accessible.