ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding that assigns codes 0 to 127 to letters, digits, punctuation, and control characters. It underpins most text formats and is a subset of Unicode.

What are control characters?

Codes 0 to 31 plus 127 are non-printing control characters such as tab (9), line feed (10), and carriage return (13). They direct devices rather than display a glyph, so the table shows their abbreviations like HT, LF, and CR.

Which codes are the letters and digits?

Digits 0 to 9 are codes 48 to 57, uppercase A to Z are 65 to 90, and lowercase a to z are 97 to 122. Uppercase and lowercase letters are exactly 32 apart, which is why flipping bit 5 changes case.

Can I look up characters above 127?

No. Codes above 127 are not ASCII — they belong to extended encodings or Unicode. This table covers standard 7-bit ASCII only; use the character-to-code tool for arbitrary Unicode characters.

How do I enter a hex code?

Prefix it with 0x, for example 0x41 for the letter A. Plain numbers are read as decimal, and a single typed character is matched directly to its code.

What is the ASCII Code Table Lookup?

Browse the full 7-bit ASCII table (codes 0-127) and look up any character by decimal code, hex code, or by typing the symbol. Shows decimal, hex, octal, and binary for every code, all in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

ASCII Code Table Lookup

Name: ASCII Code Table Lookup
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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What ASCII is

ASCII (American Standard Code for Information Interchange) is the 7-bit encoding that maps the numbers 0 through 127 to the basic Latin letters, digits, punctuation, and a set of control characters. Developed in the early 1960s and standardised in 1963, it is the historical foundation of digital text and the first 128 code points of Unicode — every ASCII character has the same code in UTF-8.

How the lookup works

The lookup accepts three input styles. A bare number like 65 is read as a decimal code; a value prefixed with 0x such as 0x41 is read as hexadecimal; and a single typed character is matched to its own code. The tool validates that the result lands in the ASCII range 0–127 and then highlights that row in the full table.

Each row shows the same code in four bases — decimal, hexadecimal, octal, and binary — so you can read whichever your task needs. Control characters (0–31 and 127) cannot be displayed as glyphs, so the table substitutes their standard abbreviations such as NUL, HT (tab), LF (newline), and DEL.

The three regions of the ASCII table

Control characters (0–31 and 127) are non-printing codes that direct behaviour. The ones you encounter most often in programming:

Code	Abbrev	Common name
9	HT	Tab
10	LF	Newline (Unix line ending)
13	CR	Carriage return (Windows uses CR+LF)
27	ESC	Escape (starts ANSI terminal sequences)
0	NUL	Null terminator (C string terminator)

Printable characters (32–126) are what you see on screen: space (32), digits (48–57), uppercase letters (65–90), lowercase letters (97–122), and punctuation scattered through the remaining ranges.

DEL (127) is a legacy delete character from the teletype era and is treated as a control character despite being at the top of the printable range.

Useful patterns to remember

Uppercase and lowercase letters differ by exactly 32. A = 65, a = 97, difference = 32. In binary, this corresponds to bit 5 (value 32) being off for uppercase and on for lowercase. Toggling that bit toggles case for any letter — a technique used in very tight assembly code.
Digit characters start at 48. The character '0' is code 48, not 0. To convert the character '5' to the integer 5, subtract 48. This subtraction appears in virtually every hand-rolled number parser.
Null byte (0) terminates C strings. C stores strings as sequences of bytes ended by a NUL (code 0), not by storing the length. Nearly every security vulnerability involving buffer overflows traces back to how programs handle (or mishandle) this convention.

Example

Looking up 65, 0x41, or A all land on the same row: the letter A, hex 0x41, octal 101, binary 01000001. The space character is code 32, the digit 0 is code 48, and DEL is code 127.

Codes above 127 fall outside standard ASCII. The first 128 Unicode code points match ASCII exactly, so any ASCII text is also valid UTF-8 — but the reverse is not true.