Unicode & ASCII

ASCII Table Reference

An interactive, fully searchable reference chart for the foundational 128 characters of the American Standard Code for Information Interchange.

Dec	Hex	Bin	Char	Description
0	0x00	00000000	NUL	Null character
1	0x01	00000001	^A	Control char
2	0x02	00000010	^B	Control char
3	0x03	00000011	^C	Control char
4	0x04	00000100	^D	Control char
5	0x05	00000101	^E	Control char
6	0x06	00000110	^F	Control char
7	0x07	00000111	^G	Control char
8	0x08	00001000	^H	Control char
9	0x09	00001001	TAB	Horizontal Tab
10	0x0A	00001010	LF	Line Feed
11	0x0B	00001011	^K	Control char
12	0x0C	00001100	^L	Control char
13	0x0D	00001101	CR	Carriage Return
14	0x0E	00001110	^N	Control char
15	0x0F	00001111	^O	Control char
16	0x10	00010000	^P	Control char
17	0x11	00010001	^Q	Control char
18	0x12	00010010	^R	Control char
19	0x13	00010011	^S	Control char
20	0x14	00010100	^T	Control char
21	0x15	00010101	^U	Control char
22	0x16	00010110	^V	Control char
23	0x17	00010111	^W	Control char
24	0x18	00011000	^X	Control char
25	0x19	00011001	^Y	Control char
26	0x1A	00011010	^Z	Control char
27	0x1B	00011011	^[	Control char
28	0x1C	00011100	^\	Control char
29	0x1D	00011101	^]	Control char
30	0x1E	00011110	^^	Control char
31	0x1F	00011111	^_	Control char
32	0x20	00100000	SPACE	Space
33	0x21	00100001	!	Printable character
34	0x22	00100010	"	Printable character
35	0x23	00100011	#	Printable character
36	0x24	00100100	$	Printable character
37	0x25	00100101	%	Printable character
38	0x26	00100110	&	Printable character
39	0x27	00100111	'	Printable character
40	0x28	00101000	(	Printable character
41	0x29	00101001	)	Printable character
42	0x2A	00101010	*	Printable character
43	0x2B	00101011	+	Printable character
44	0x2C	00101100	,	Printable character
45	0x2D	00101101	-	Printable character
46	0x2E	00101110	.	Printable character
47	0x2F	00101111	/	Printable character
48	0x30	00110000	0	Printable character
49	0x31	00110001	1	Printable character
50	0x32	00110010	2	Printable character
51	0x33	00110011	3	Printable character
52	0x34	00110100	4	Printable character
53	0x35	00110101	5	Printable character
54	0x36	00110110	6	Printable character
55	0x37	00110111	7	Printable character
56	0x38	00111000	8	Printable character
57	0x39	00111001	9	Printable character
58	0x3A	00111010	:	Printable character
59	0x3B	00111011	;	Printable character
60	0x3C	00111100	<	Printable character
61	0x3D	00111101	=	Printable character
62	0x3E	00111110	>	Printable character
63	0x3F	00111111	?	Printable character
64	0x40	01000000	@	Printable character
65	0x41	01000001	A	Printable character
66	0x42	01000010	B	Printable character
67	0x43	01000011	C	Printable character
68	0x44	01000100	D	Printable character
69	0x45	01000101	E	Printable character
70	0x46	01000110	F	Printable character
71	0x47	01000111	G	Printable character
72	0x48	01001000	H	Printable character
73	0x49	01001001	I	Printable character
74	0x4A	01001010	J	Printable character
75	0x4B	01001011	K	Printable character
76	0x4C	01001100	L	Printable character
77	0x4D	01001101	M	Printable character
78	0x4E	01001110	N	Printable character
79	0x4F	01001111	O	Printable character
80	0x50	01010000	P	Printable character
81	0x51	01010001	Q	Printable character
82	0x52	01010010	R	Printable character
83	0x53	01010011	S	Printable character
84	0x54	01010100	T	Printable character
85	0x55	01010101	U	Printable character
86	0x56	01010110	V	Printable character
87	0x57	01010111	W	Printable character
88	0x58	01011000	X	Printable character
89	0x59	01011001	Y	Printable character
90	0x5A	01011010	Z	Printable character
91	0x5B	01011011	[	Printable character
92	0x5C	01011100	\	Printable character
93	0x5D	01011101	]	Printable character
94	0x5E	01011110	^	Printable character
95	0x5F	01011111	_	Printable character
96	0x60	01100000	`	Printable character
97	0x61	01100001	a	Printable character
98	0x62	01100010	b	Printable character
99	0x63	01100011	c	Printable character
100	0x64	01100100	d	Printable character
101	0x65	01100101	e	Printable character
102	0x66	01100110	f	Printable character
103	0x67	01100111	g	Printable character
104	0x68	01101000	h	Printable character
105	0x69	01101001	i	Printable character
106	0x6A	01101010	j	Printable character
107	0x6B	01101011	k	Printable character
108	0x6C	01101100	l	Printable character
109	0x6D	01101101	m	Printable character
110	0x6E	01101110	n	Printable character
111	0x6F	01101111	o	Printable character
112	0x70	01110000	p	Printable character
113	0x71	01110001	q	Printable character
114	0x72	01110010	r	Printable character
115	0x73	01110011	s	Printable character
116	0x74	01110100	t	Printable character
117	0x75	01110101	u	Printable character
118	0x76	01110110	v	Printable character
119	0x77	01110111	w	Printable character
120	0x78	01111000	x	Printable character
121	0x79	01111001	y	Printable character
122	0x7A	01111010	z	Printable character
123	0x7B	01111011	{	Printable character
124	0x7C	01111100	\|	Printable character
125	0x7D	01111101	}	Printable character
126	0x7E	01111110	~	Printable character
127	0x7F	01111111	DEL	Delete

The Foundation of Modern Computing

Published comprehensively in 1963, ASCII is arguably the single most important data encoding standard ever created in computer science. Before ASCII, different hardware manufacturers (like IBM, Apple, and TeleType) used completely different mathematical codes to represent letters. This devastating fragmentation meant an IBM computer could not reliably send a text file over a network to a TeleType machine without the text turning into complete gibberish.

ASCII successfully standardized the digital alphabet into a strict 7-bit system, mathematically allowing for exactly 128 unique entries. Numbers 0-31 were rigidly assigned as "Control Characters" to manage physical printer hardware actions. Number 32 is the spacebar. Numbers 33-126 contain all the printable characters (letters, numbers, and punctuation), and 127 is uniquely reserved for the 'Delete' command.

Even modern, vastly superior encoding standards like UTF-8 intentionally mirror the ASCII table for their very first 128 characters. This masterstroke guarantees perfect backward compatibility across the internet. If you write a standard english text file today, it is structurally identical to a text file written in the 1970s.

Frequently Asked Questions

What exactly does ASCII stand for?

ASCII strictly stands for the 'American Standard Code for Information Interchange'. Developed in 1963, it is the foundational character encoding standard for all electronic communication, mathematically mapping exactly 128 english letters, numbers, and control codes to specific 7-bit numeric values.

What are 'Control Characters' in the ASCII table?

The very first 32 characters (0 through 31) in the ASCII table are entirely non-printable control characters. Historically in the 1970s, they were used to physically control hardware like mechanical Teletype printers (e.g., triggering a Carriage Return, a Line Feed, or ringing a Bell). Today, while printers have evolved, these codes are still heavily used for text file formatting and low-level network protocol framing.

Why does the ASCII table only have 128 characters?

The original ASCII standard was strictly designed as a 7-bit architecture. In binary mathematics, 7 bits allow for exactly 128 unique combinations (2^7 = 128). This was enough to comfortably fit the uppercase and lowercase English alphabet, numbers 0-9, standard punctuation, and the necessary hardware control codes. It was later expanded into 8-bit 'Extended ASCII', which allowed for 256 characters.

Is ASCII obsolete now that we have Unicode?

Absolutely not. Modern encoding standards like UTF-8 were intentionally and brilliantly engineered to be 100% backward compatible with ASCII. The first 128 characters of the modern Unicode system are perfectly identical to the 1963 ASCII table. This guarantees that a standard English text file written today is structurally identical at the byte-level to a text file written in 1985.

Why do developers need Hexadecimal values?

While humans prefer Decimal (base-10), computers naturally operate in Binary (base-2). Hexadecimal (base-16) is the perfect compromise. A single Hexadecimal character exactly represents 4 bits (a nibble). Two Hex characters perfectly represent 1 byte (8 bits). This makes Hexadecimal the most concise, readable format for low-level developers to inspect raw memory dumps and ASCII file structures.

Why is the Spacebar considered a character?

In computer science, a 'space' is not just emptiness; it is physical data that must be stored in memory to tell the rendering engine to move the cursor forward. In the ASCII table, the spacebar is officially mapped to Decimal 32 (Hex 20). It marks the exact boundary between the non-printable hardware control characters and the printable symbols.