UUEncode / UUDecode Converter

Encode text into the classic Unix uuencode format (with begin 644 name header and ` / end trailer) or decode uuencoded text back to readable text. Lines hold at most 45 bytes; each line begins with a length character. Decoding tolerates a missing begin/end wrapper.
All processing happens locally in your browser — nothing is uploaded.
File name in header: goes into begin 644 <name> (mode 644 fixed).
Encode Text → UU: Your text becomes UTF-8 bytes, grouped 45 per line. Each line is prefixed by a length character (32 + byte count, so 45 = M), then three bytes become four printable characters in the 6-bit alphabet space–_. Short last groups are padded inside their final group.
Decode UU → Text: The begin mode name line, the final ` terminator and the end line are all recognized but optional — paste any block of uuencoded lines. A line whose length character is ` or space (0 bytes) stops the data. Non-ASCII or out-of-range characters are rejected with their position; the decoded bytes are interpreted as UTF-8.
Input
Output
Ctrl+Enter in the input runs the active mode.
Pick a direction and run it. All processing stays in your browser.
uuencode format:
Header: begin 644 weqsoft.txt  — literal word begin, an octal permission mode and the file name.
Data lines: each line starts with a length character equal to byte count + 32 (45 bytes = M), followed by the 6-bit groups — three bytes → four characters in the range space–_ (32–95). The known classic vector Cat encodes as the line #0V%T.
Trailer: a terminator line of a single backtick ` followed by the line end.
Notes: this tool works on UTF-8 text, so any Unicode (including emoji and Chinese) round-trips perfectly; binary files would decode to non-UTF-8 bytes, which this text tool reports as an error. Line endings are shown as LF (browsers normalize CRLF in form fields).