Convert UTF-8 to Octal

Base 8. Digits 0-7 only. Each UTF-8 byte (0-255 decimal = 0x00-0xFF hex) fits in at most 3 octal digits (000-377). Historically common on PDP minicomputers and Unix file permissions.

Different languages adopted different conventions. 0o: Python 3, JS ES2015 – the modern unambiguous form. : C/C++/Python string byte-escape ("110" = “H”). 0: K&R C and pre-3.0 Python (0110 = “H”) – visually identical to the leading-zero-padded form, source of many bugs. None: plain digits for network dumps.

That’s the source of K&R-era bugs. 0110 could mean octal 110 (= 72 decimal = ‘H’) OR a 4-digit zero-padded value. Modern languages avoid octal by default for this exact reason. This tool treats a leading 0 as the prefix only when followed by valid octal digits.

Pads each token to 11 octal digits – enough to represent a full 32-bit unsigned value. Rarely useful for UTF-8 (which is byte-oriented), but available for compatibility with fixed-width binary dumps.

Each token must be octal digits (0-7) only after prefix strip. Anything else throws with the position. Token values >255 (octal > 377) throw because they can’t be valid bytes. The assembled byte sequence is run through fatal-mode UTF-8 decoder – invalid UTF-8 throws explicitly rather than producing U+FFFD.

3-digit padded octal: 3 chars per byte (vs hex’s 2). Plus separator. So octal is ~50% larger than hex for the same data. The trade-off is human readability: octal digits are unambiguous (0-7 only), hex letters can be confusing in lowercase (e.g., 0b = boolean prefix vs 0b = binary prefix).

UTF-8 byte sequences come from TextEncoder. 🌍 (U+1F30D) produces 4 bytes: 360 237 214 215 octal (= F0 9F 8C 8D hex). Naive implementations looping charCodeAt would see UTF-16 surrogate pairs instead.

No. The conversion runs entirely in your browser – nothing is sent to a server, logged, or stored, and the tool keeps working offline once the page has loaded.

200,000 characters. Octal output peaks at ~3.5× the input character count.

The Unicode→Octal tool operates on codepoints (one octal per character) and supports 7-digit padding for the full U+10FFFF range. This UTF-8→Octal tool operates on UTF-8 bytes (1-4 per character) with 3-digit padding per byte.