Encoding Tools
Quoted-Printable Encoder/Decoder - RFC 2045 QP Online
Encode text to Quoted-Printable (QP) or decode QP back to plain text. Implements RFC 2045 Section 6.7 with proper 76-char line wrapping and soft line breaks.
Quoted-Printable Encoder / Decoder
Quoted-Printable (QP) is a MIME content-transfer encoding defined in RFC 2045. It is designed
for data that is mostly US-ASCII but contains occasional non-ASCII or control characters. Each
non-printable byte is replaced with =XX where XX is the uppercase hexadecimal value
of the byte.
Line length
RFC 2045 mandates that encoded lines must not exceed 76 characters. Longer lines are broken
with a trailing = followed by CRLF: a "soft line break". When decoded the soft break
is simply discarded.
Compared to Base64
Quoted-Printable is most efficient when the data is predominantly ASCII (the overhead for ASCII characters is zero). For binary or heavily non-ASCII data, Base64 produces shorter output because it uses a fixed 4-chars-per-3-bytes expansion rather than potentially 3 characters per byte.
Where QP appears today
Quoted-Printable appears in two main email contexts:
- Email headers (RFC 2047 encoded-word format): non-ASCII characters in Subject,
From, or To headers are encoded as
=?UTF-8?Q?...?=. For example, a subject line with an accented character appears as=?UTF-8?Q?Caf=C3=A9_menu?=in raw email source. - Email bodies: a MIME part with
Content-Transfer-Encoding: quoted-printableuses QP encoding for the body text. This is the most common encoding for HTML and plain-text email bodies that contain non-ASCII characters.
Decoding an email body
To decode a QP-encoded email using this tool:
- In your email client, view the raw/source of the message.
- Locate the MIME part header
Content-Transfer-Encoding: quoted-printable. - Copy everything after the blank line that follows the headers — that is the encoded body.
- Paste it into the Decode tab of this tool to recover the original text.