Look up an ASCII code in decimal, hex and binary

Convert an ASCII character or control value among decimal, hexadecimal, octal, and binary notation.

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ToolASCII Table Reference
Input
Output
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How it works

Every 7-bit ASCII value from 0 through 127 is represented in four radices, with binary padded to eight visible digits for byte-oriented work. A separately labelled Latin-1 Supplement covers printable values 160 through 255 without redefining them as ASCII.

Formula
hex 0x41 = decimal 65 = octal 0o101 = binary 01000001 = A
  • Bare numeric input is decimal, 0x selects hexadecimal, and 0o selects octal.
  • One-character lookup is case-sensitive because uppercase and lowercase letters occupy different code positions.

Worked example

Character 65
Look up by decimal code
Input
											65
Output
												1 of 224 entries match "65":

Dec  Hex  Oct  Binary    Char  Name                  
65   41   101  01000001  A     Latin capital letter A

When to use this

Protocol debugging identifies CR and LF controls, source-code escapes translate numeric byte notation, and hex dumps map printable byte values back to ASCII characters.

Edge cases

  • 41 means decimal 41, while 0x41 means hexadecimal 65 and finds A; the prefix controls the radix.
  • A resolves to 65 and a resolves to 97 because a literal-character search preserves case.
  • 160 is a Latin-1 non-breaking space rather than ASCII, so it appears only in the separately named supplement.

References