ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding standard that assigns numerical values (0–127) to 128 characters, including English letters, digits, punctuation marks, and control codes.
Since Base64 takes arbitrary 8-bit bytes and maps them into printable ASCII characters (codes 32–126), understanding the ASCII table is essential when debugging binary-to-text data.
Printable Characters Reference Table (Codes 32–126)
| Dec | Hex | Binary | Char | Description |
|---|---|---|---|---|
| 32 | 0x20 | 00100000 | [space] | Space |
| 33 | 0x21 | 00100001 | ! | Exclamation mark |
| 34 | 0x22 | 00100010 | " | Double quote |
| 35 | 0x23 | 00100011 | # | Number sign |
| 36 | 0x24 | 00100100 | $ | Dollar sign |
| 37 | 0x25 | 00100101 | % | Percent sign |
| 38 | 0x26 | 00100110 | & | Ampersand |
| 43 | 0x2B | 00101011 | + | Plus sign (Base64 index 62) |
| 47 | 0x2F | 00101111 | / | Slash (Base64 index 63) |
| 48–57 | 0x30–0x39 | 00110000+ | 0–9 | Digits 0 through 9 |
| 61 | 0x3D | 00111101 | = | Equal sign (Base64 padding) |
| 65–90 | 0x41–0x5A | 01000001+ | A–Z | Uppercase English letters |
| 95 | 0x5F | 01011111 | _ | Underscore (Base64url index 63) |
| 97–122 | 0x61–0x7A | 01100001+ | a–z | Lowercase English letters |
Common ASCII Control Codes
0x00(NUL) - Null character0x09(HT) - Horizontal Tab (\t)0x0A(LF) - Line Feed / Newline (\n)0x0D(CR) - Carriage Return (\r)