Usenet binary posting · ~2% overhead
Usenet binary posting format designed to be denser than uuencode by using most of the 8-bit range (bytes 0–255) directly. Only escapes NUL (0), LF (10), CR (13), and TAB (9). ~2% overhead vs. uuencode's ~33%.
Text / Bytes → yEnc box — the encoded output appears instantly in yEnc-encoded.Copy result to grab the yEnc data to your clipboard — the encode output field is read-only.yEnc → Text box and the decoded text appears in Decoded text.Clear any time to reset a box and start over.yEnc is the de facto standard for binary newsgroup posts. Preview exactly how raw bytes are escaped before you compose a post.
Unlike Base64 and uuencode (about 33% overhead), yEnc passes most bytes through unchanged, so encoded output stays close to the input size.
See precisely which bytes get escaped — NUL, TAB, LF, and CR — and how every other byte value passes through as-is.
Paste a yEnc payload from a newsreader to recover the original bytes and text for inspection or verification.
Put the same data through yEnc, Base64, and uuencode to see the size and readability tradeoffs for your use case.
All encoding and decoding runs locally in your browser. Nothing is uploaded, stored, or logged — safe for sensitive payloads.
yEnc is an encoding for posting binary files to Usenet. It was designed to be denser than uuencode and Base64 by passing most of the 8-bit range (bytes 0–255) through unchanged.
Only four byte values are escaped — NUL (0), TAB (9), LF (10), and CR (13) — each written as = plus a marker character. Every other byte passes through as-is, keeping the output nearly 1:1 with the input.
yEnc has roughly 2% overhead, versus about 33% for both uuencode and Base64 (which expands every 3 bytes into 4). That lower overhead is why yEnc is preferred for Usenet binaries.
No. Base64 maps every 3 bytes to 4 printable characters and always inflates the size. yEnc only escapes the bytes that need it, so most data stays unchanged and stays much smaller on the wire.
This tool performs the core byte-level encode/decode. A full yEnc post also wraps the data with article headers like =ybegin, =ypart, and =yend plus CRC checks — this tool focuses on the raw data conversion, not the article framing.
No. yEnc is fully reversible encoding with no security — anyone can decode it. It only makes data safe to transmit over text-based Usenet; it does not hide it.
Never. All encoding and decoding happens locally in JavaScript. Your input is not sent to, stored on, or logged by any server.