Octal encode

Three octal digits per byte, zero padded, with a space between bytes. Values run from 000 for a zero byte to 377 for 255, because 255 in base 8 is 377. The padding is always applied, so every group is exactly three characters wide and the output stays aligned.

Because a byte only holds values 0 to 255, and 255 written in base 8 is 377. Three octal digits can express up to 511, so the top of the range is simply never reached. If you see a group above 377 in some other text, it is not a byte-wise octal encoding.

No. Permissions use three or four octal digits to describe one set of flags, not a stream of bytes. For that, use the chmod calculator, which turns rwx settings into the octal mode and back. This tool has no idea what your bytes mean; it writes each one in base 8.

It is encoded as its UTF-8 bytes, so one character can produce two, three or four groups. The accented letter e-acute becomes 303 251, and an emoji becomes four groups. Octal here is a byte-level notation, not a character-level one. If you want one number per character instead, use Charcode encode, which writes Unicode code points.

No, there are no options on this tool. The output is bare three-digit groups separated by single spaces, with no backslashes, no leading zero prefix and no commas. Paste it into an editor and add whatever syntax your target needs with a find and replace; the digits themselves are already right for a C escape.

No. Conversion happens in a Web Worker on your device, with no upload and no stored copy. There is no account, no history and no server request at any point, and the site keeps working once you are offline. Drop several files together and each one gets its own separate result.