Quoted Printable Encoder Decoder
Encode MIME text with RFC 2045 wrapping or decode quoted-printable bytes and soft breaks.
Paste email body text, MIME content, or Quoted-Printable text with equals escapes such as =C3=A9 and soft line breaks ending with =.
Options
Encoding always escapes trailing spaces/tabs and bytes outside the RFC 2045 printable range. Wrapping at 76 characters keeps generated MIME body lines conformant.
Output
Converted Quoted-Printable output will appear here.
Quoted-Printable is a MIME transfer encoding for bytes
Quoted-Printable keeps many printable ASCII bytes readable and writes other bytes as an equals sign followed by two hexadecimal digits. A UTF-8 character can therefore occupy several escapes: é becomes the UTF-8 bytes C3 A9 and is represented as=C3=A9.
The transfer encoding does not identify the character set by itself. MIME normally carries charset information in a Content-Type header. Choose UTF-8 only when those decoded bytes are expected to be UTF-8; invalid UTF-8 is reported instead of silently replaced. The ISO-8859-1 option maps each byte directly to the corresponding U+0000-U+00FF character and does not emulate Windows-1252.
The 76-character line limit includes the soft-break equals sign
RFC 2045 limits encoded Quoted-Printable lines to 76 characters, excluding the terminating CRLF. A trailing equals sign marks a soft break, meaning the next physical line continues the same logical line. The encoder wraps without splitting an =XXescape and counts that final equals sign inside the limit.
Disabling wrapping is kept for debugging existing systems, but the result is flagged when any line exceeds the MIME limit. CRLF is the canonical MIME line ending; LF or preserved local newlines are available for inspection and are reported as non-canonical when encoding.
Trailing spaces and tabs
Space or tab at the end of an encoded line must be escaped because mail transports may add or remove trailing whitespace. The encoder always writes those bytes as =20 or =09.
Transport padding on decode
RFC 2045 tells decoders to discard trailing space or tab found on an encoded physical line. Lenient decode follows that rule and reports when such transport padding was removed.
Strict decode is for syntax checking; lenient decode is for damaged mail
Strict mode rejects malformed equals escapes, non-ASCII literal characters, non-CRLF soft breaks, and physical lines longer than 76 characters. Lenient mode keeps recoverable malformed text where possible and reports what was accepted, which is useful when examining mail that has already passed through gateways or copy/paste.
Auto detect is only a convenience heuristic. Plain text containing a sequence such as =3D can look like encoded content, so select Decode explicitly when validating a raw MIME part.
Body Quoted-Printable is not MIME header Q-encoding
The scope here is the Content-Transfer-Encoding form defined for MIME bodies. Encoded-word headers such as=?UTF-8?Q?...?= use related but different rules from RFC 2047, including underscore handling. Do not feed an entire encoded-word header here and assume it has been validated as a mail header.
RFC 2045 is the wire-format reference
RFC 2045 section 6.7 defines Quoted-Printable, including legal literal octets, trailing whitespace treatment, soft line breaks, and the 76-character line limit. Mail software may apply additional MIME header and charset rules outside this body's transfer encoding.