Useful for debugging character-encoding bugs (mojibake, UTF-8 double-encoding), teaching binary math, decoding CTF puzzles, or preparing hand-crafted test vectors. UTF-8 mode is the correct choice 99% of the time in modern systems — it's what HTTP, JSON, and filenames use. ASCII mode is only right when you're specifically working with legacy protocols. Alternative: `xxd -b` on a Unix shell handles the same encode direction, but doesn't have a decoder baked in.
The letter 'A' across encodings:
ASCII 7-bit: 1000001
ASCII 8-bit: 01000001
UTF-8: 01000001
UTF-16: 0000000001000001Last updated: 2026-04-24