Email Subject Decoder
Remove ASCII codes and decode MIME encoded email subjects instantly
charset: UTF-8, ISO-8859-1, etc.
encoding: Q (Quoted-Printable) or B (Base64)
text: The encoded content
Table of Contents
What is MIME Encoding in Email Subjects?
MIME (Multipurpose Internet Mail Extensions) encoding is used in email headers to represent non-ASCII characters safely. When an email subject contains special characters, emojis, or text in languages like Chinese, Japanese, or Arabic, it must be encoded to ensure proper transmission across email systems.
This tool decodes these encoded subjects back to their readable form, removing the =?UTF-8?Q?...?= wrapper and converting hex codes back to actual characters.
Multi-Language
Supports UTF-8, ISO-8859-1, Windows-1252, and more character sets
Dual Encoding
Handles both Quoted-Printable (Q) and Base64 (B) encoding
Bulk Processing
Decode multiple email subjects at once, one per line
Two-Way
Both decode and encode email subjects as needed
How to Use This Tool
- Choose mode - Select Decode to convert encoded subjects, or Encode to create encoded subjects
- Paste your subject - Enter one or more encoded email subjects (one per line)
- Click Decode/Encode - The tool processes your input instantly
- View results - See decoded text with encoding details
- Copy result - Use the copy button to copy the decoded text
Encoding Types Explained
Quoted-Printable (Q)
Uses =XX format where XX is the hex value of the character. Underscores represent spaces. Example: =?UTF-8?Q?Hello_World?=
Base64 (B)
Encodes the entire text as a Base64 string. More compact for non-ASCII heavy text. Example: =?UTF-8?B?SGVsbG8gV29ybGQ=?=
Frequently Asked Questions (FAQs)
MIME (Multipurpose Internet Mail Extensions) encoding is used in email headers to represent non-ASCII characters. Email subjects containing special characters, emojis, or non-English text are encoded using formats like =?UTF-8?Q?...?= (Quoted-Printable) or =?UTF-8?B?...?= (Base64).
This tool supports: Quoted-Printable (Q) - encodes special characters as =XX hex codes, Base64 (B) - encodes text as base64 string, and various character sets including UTF-8, ISO-8859-1, Windows-1252, and more.
Email protocols (SMTP) were originally designed for ASCII text only. To support international characters, emojis, and special symbols, email clients encode the subject line using MIME encoding. The format =?charset?encoding?encoded_text?= tells the receiving client how to decode it.
Simply paste multiple encoded subjects, one per line. The tool will decode each line separately and display all decoded results. You can also use the bulk mode to process many subjects efficiently.
Yes! Switch to "Encode" mode to convert plain text subjects into MIME-encoded format. This is useful when you need to manually craft email headers or test email systems.
