Quoted-Printable Converter

What this tool does

Quoted-Printable Converter turns readable text into the 7-bit-safe Quoted-Printable format used in email bodies, with 76-character lines and soft line breaks, and decodes it back. It also encodes and decodes the encoded-words found in Subject and From headers, in both Q and Base64 forms.

Email was designed for 7-bit ASCII with lines of limited length, so text containing accented letters, symbols or very long lines must be transformed before sending. Quoted-Printable, defined in RFC 2045, keeps ordinary ASCII readable and replaces every other byte with “=” and two hex digits, so the UTF-8 bytes of “é” become =C3=A9. Lines longer than 76 characters are split with a soft line break, an “=” at the end of the line that the decoder removes. When you open the raw source of an email, or a .eml file, this is the text you see.

This converter encodes text to the bytes of UTF-8 or ISO-8859-1 and writes them in Quoted-Printable with correct handling of “=”, trailing spaces and tabs, and soft breaks at 76 characters, using CRLF line endings as email requires. The decoder removes soft breaks and trailing whitespace, converts each =XX escape and reports malformed escapes. Header mode handles RFC 2047 encoded-words such as =?UTF-8?Q?Gr=C3=BC=C3=9Fe?=, using underscores for spaces and keeping each word within 75 characters; the header decoder also accepts Base64 (?B?) words. Processing is entirely local.

How to use Quoted-Printable Converter

1. Paste raw email text, a header value or plain text into the Input box.
2. Choose a Mode: encode or decode a body, or encode or decode header words.
3. Pick the Character set given in the email’s Content-Type header, usually UTF-8.
4. For encoding, set the Maximum line length and Line endings; 76 and CRLF follow the standard.
5. Copy or download the result, or use “Use output as input” to check the round trip.

Tips for better results

• If decoded text shows “é” instead of “é”, the message was UTF-8 but was decoded as Latin-1. Switch the character set.
• A line ending in “=” is a soft break and is joined to the next line when decoding.
• Spaces at the end of a line are encoded as =20, because mail servers may strip trailing whitespace.
• In header Q encoding an underscore means a space; a real underscore is written =5F.

Common use cases

• Reading the body of an email saved as .eml or viewed with “Show original”.
• Decoding an unreadable Subject line in mail server logs.
• Preparing a MIME part by hand when testing an SMTP integration.
• Debugging why special characters appear broken in a marketing email.

Common mistakes to avoid

• Decoding Base64 message parts with a Quoted-Printable decoder. Check the Content-Transfer-Encoding header first.
• Forgetting that “=” itself must be encoded as =3D, which corrupts values such as URLs with query strings.
• Splitting a header encoded-word in the middle of a multi-byte UTF-8 character, which many clients cannot decode. This tool never does that.