ASCII

ASCII (American Standard Code for Information Interchange) is a character encoding standard that gives each of 128 characters a number from 0 to 127: the English letters A–Z and a–z, the digits 0–9, punctuation, the space, and 33 non-printing control characters such as tab, line feed and carriage return.

Because 128 values fit in 7 bits, every ASCII character can be stored in one byte, so computers and devices can exchange plain text using the same numbers. For example, uppercase A is 65, lowercase a is 97 (always 32 more than its capital), the digit 0 is 48 and a space is 32.

ASCII was first published in 1963. Modern text uses Unicode, usually encoded as UTF-8, which keeps the first 128 code points identical to ASCII, so plain ASCII text is also valid UTF-8. Codes 128–255 are not part of ASCII: so-called extended ASCII means different characters depending on the code page in use, such as ISO 8859-1 or Windows-1252. See the full ASCII table, with a converter between characters and codes, at ihelpyou.in/ascii-table.

Character:  H    e    l    l    o
Decimal:    72   101  108  108  111
Hex:        48   65   6C   6C   6F
Binary:     01001000 01100101 01101100 01101100 01101111