ASCII Table

Standard ASCII defines 128 characters, numbered 0 to 127. That splits into 33 non-printing control codes (0–31 and 127, like tab, line feed, and escape) and 95 printable characters (32–126) — the space, digits, letters, and punctuation. Everything above 127 is not ASCII; it belongs to an extended set like Windows-1252 or a Unicode encoding.

'Extended ASCII' isn't a single standard — it's a loose name for any encoding that uses values 128–255 on top of ASCII, and several incompatible ones exist (Windows-1252, ISO-8859-1, Code Page 437). This table's extended tab uses Windows-1252, the web's default, so 128–159 show glyphs like the euro sign and trademark where ISO-8859-1 would place control codes.

The uppercase letters were assigned 65–90 and lowercase 97–122, exactly 32 apart. That gap is a single bit (0x20), so flipping one bit converts between cases — a deliberate design choice that made early text processing simple. The digits 0–9 sit at 48–57 for the same kind of convenience.