Look up an ASCII code

Decimal, hex, octal, binary, and the character — for one code point or a browsable table of all 128.

Tools used in this guide

The job

A protocol spec says 'send 0x1B' — that's ESC. A regex needs a tab escape — that's 0x09. Flipping between a number and its character is a five-second lookup, not a memory test.

Look it up

Type a character to get its codes, or a number (decimal, 0x hex, 0o octal, 0b binary) to get the character. The full table below shows all 128 entries with all four bases at once; control characters show their names (NUL, BEL, DEL).

Codes 0–31 and 127 are control characters — they don't print, but protocols still use them.
A is 0x41, a is 0x61; digits start at 0x30. Those three offsets cover most lookups.

Worked example

Escaping a byte in a C string: DEL shows as 127 / 0x7F / 0o177 / 0b1111111 — pick the base your language wants.

Where it stops

ASCII only: codes 0–127. Anything outside — é, emoji, Japanese text — is Unicode, which the character counter shows per code point instead. The table renders in-browser; nothing is fetched.