Unix-to-Unix · pre-MIME · historical
Pre-MIME Unix binary-to-text encoding, used for sending files over email and Usenet in the 1980s–90s. Every 3 bytes become 4 printable characters (shifted by 32). Produces begin/end wrappers with file mode and name.
Text / Bytes → UUencoded box — the encoded block appears instantly in the UUencoded panel.begin 644 data and ends with ` followed by end, matching classic uuencode.Copy result to copy the entire encoded block (wrappers included) to your clipboard.begin/end lines — into the UUencoded → Text box and the original text appears in Decoded text.Clear any time to reset a box and start over.Attachments shared over email and Usenet in the 1980s–90s were often uuencoded. Decode old .uue blocks to recover the original data.
See how 3 bytes become 4 printable characters (each shifted by 32) — the direct ancestor of Base64 and a classic piece of Unix history.
Convert binary to printable ASCII that survives 7-bit transports like old mail systems and terminal pipes that can't carry raw bytes.
Inspect the begin/end wrappers, the 644 mode, the filename, and the per-line length byte that define uuencode.
Spot lines longer than the 45-byte maximum or a missing end marker when a decoded result looks truncated or wrong.
Everything runs in your browser. Nothing is uploaded, logged, or sent to a server — safe for sensitive files and payloads.
UUencode ("Unix-to-Unix encode") is a pre-MIME binary-to-text encoding from the early Unix era. It converts arbitrary bytes into printable ASCII so files could be sent through text-only email and Usenet.
Every 3 bytes are split into four 6-bit groups, each converted to a character by adding 32 so it stays printable. Each output line is prefixed with a length byte (also offset by 32) and holds up to 45 input bytes.
begin and end lines mean?begin marks the start and carries a file mode and name (this tool always emits begin 644 data). end marks the end of the file, and the single backtick ` is the zero-length line that precedes it.
No. They share the same goal and similar ~33% overhead, but use different algorithms and alphabets. Uuencode is the historical format; Base64 (MIME) later replaced it in email.
Because 3 input bytes become 4 output characters, a ~33% size increase, plus the begin/end wrapper and per-line length characters.
This tool decodes a single uuencoded block: it skips begin/end lines and stops at the ` line. It does not verify checksums or split multiple concatenated files.
Never. All encoding and decoding happens locally in JavaScript. Your input is not sent to, stored on, or logged by any server.