What is ASCII and what does it stand for?

ASCII stands for American Standard Code for Information Interchange. It is a character encoding standard developed in the 1960s that assigns numeric values (0-127) to characters, including English letters, digits, punctuation marks, and control characters. ASCII is the foundation of most modern character encoding systems, including UTF-8, and is essential for computers to represent and exchange text data.

How many characters are in the ASCII table?

The standard ASCII table contains 128 characters (numbered 0-127). This includes 33 control characters (0-31 and 127) that are non-printable, and 95 printable characters (32-126) that include the space character, uppercase and lowercase English letters (A-Z, a-z), digits (0-9), and common punctuation and symbols. Extended ASCII (128-255) adds another 128 characters but is not part of the original standard.

What is the difference between ASCII and Unicode?

ASCII defines only 128 characters (7 bits), covering basic English text. Unicode is a much larger standard that defines over 149,000 characters from virtually all writing systems, plus emojis and symbols. UTF-8 is the most common Unicode encoding and is backward-compatible with ASCII — the first 128 UTF-8 characters are identical to ASCII. Modern systems use UTF-8 for international text support.

What are ASCII control characters?

Control characters (ASCII 0-31 and 127) are non-printable characters originally designed to control hardware devices like printers and terminals. Common ones include: NULL (0), TAB (9), Line Feed/LF (10), Carriage Return/CR (13), and ESC (27). In the table, they are shown with caret notation (e.g., ^A for SOH, ^I for Tab). Most are rarely used today, though LF, CR, and TAB remain essential.

What is the ASCII value of A, a, 0, and space?

Uppercase 'A' has ASCII value 65 (hex 41), lowercase 'a' is 97 (hex 61), the digit '0' is 48 (hex 30), and space is 32 (hex 20). Uppercase letters span 65-90, lowercase letters span 97-122, and digits span 48-57. The difference between uppercase and lowercase is always 32, which corresponds to a single bit flip in binary.

How do I convert text to ASCII codes?

Use the Text to ASCII converter below the reference table. Type or paste your text, and the tool instantly shows the decimal ASCII code for each character, separated by spaces. For example, 'Hello' becomes '72 101 108 108 111'. You can also convert ASCII codes back to text by entering space-separated numbers in the ASCII to Text converter.

ASCII Table & Converter

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Complete ASCII reference table (0-127) with decimal, hex, octal, and binary values. Includes text to ASCII and ASCII to text converters. Searchable and filterable.

Dec	Hex	Oct	Binary	Char	Description
0	0x00	000	00000000	^@	NUL (Null)
1	0x01	001	00000001	^A	SOH (Start of Heading)
2	0x02	002	00000010	^B	STX (Start of Text)
3	0x03	003	00000011	^C	ETX (End of Text)
4	0x04	004	00000100	^D	EOT (End of Transmission)
5	0x05	005	00000101	^E	ENQ (Enquiry)
6	0x06	006	00000110	^F	ACK (Acknowledge)
7	0x07	007	00000111	^G	BEL (Bell)
8	0x08	010	00001000	^H	BS (Backspace)
9	0x09	011	00001001	^I	HT (Horizontal Tab)
10	0x0A	012	00001010	^J	LF (Line Feed)
11	0x0B	013	00001011	^K	VT (Vertical Tab)
12	0x0C	014	00001100	^L	FF (Form Feed)
13	0x0D	015	00001101	^M	CR (Carriage Return)
14	0x0E	016	00001110	^N	SO (Shift Out)
15	0x0F	017	00001111	^O	SI (Shift In)
16	0x10	020	00010000	^P	DLE (Data Link Escape)
17	0x11	021	00010001	^Q	DC1 (Device Control 1)
18	0x12	022	00010010	^R	DC2 (Device Control 2)
19	0x13	023	00010011	^S	DC3 (Device Control 3)
20	0x14	024	00010100	^T	DC4 (Device Control 4)
21	0x15	025	00010101	^U	NAK (Negative ACK)
22	0x16	026	00010110	^V	SYN (Synchronous Idle)
23	0x17	027	00010111	^W	ETB (End of Trans. Block)
24	0x18	030	00011000	^X	CAN (Cancel)
25	0x19	031	00011001	^Y	EM (End of Medium)
26	0x1A	032	00011010	^Z	SUB (Substitute)
27	0x1B	033	00011011	^[	ESC (Escape)
28	0x1C	034	00011100	^\	FS (File Separator)
29	0x1D	035	00011101	^]	GS (Group Separator)
30	0x1E	036	00011110	^^	RS (Record Separator)
31	0x1F	037	00011111	^_	US (Unit Separator)
32	0x20	040	00100000	SP	Space
33	0x21	041	00100001	!
34	0x22	042	00100010	"
35	0x23	043	00100011	#
36	0x24	044	00100100	$
37	0x25	045	00100101	%
38	0x26	046	00100110	&
39	0x27	047	00100111	'
40	0x28	050	00101000	(
41	0x29	051	00101001	)
42	0x2A	052	00101010	*
43	0x2B	053	00101011	+
44	0x2C	054	00101100	,
45	0x2D	055	00101101	-
46	0x2E	056	00101110	.
47	0x2F	057	00101111	/
48	0x30	060	00110000	0
49	0x31	061	00110001	1
50	0x32	062	00110010	2
51	0x33	063	00110011	3
52	0x34	064	00110100	4
53	0x35	065	00110101	5
54	0x36	066	00110110	6
55	0x37	067	00110111	7
56	0x38	070	00111000	8
57	0x39	071	00111001	9
58	0x3A	072	00111010	:
59	0x3B	073	00111011	;
60	0x3C	074	00111100	<
61	0x3D	075	00111101	=
62	0x3E	076	00111110	>
63	0x3F	077	00111111	?
64	0x40	100	01000000	@
65	0x41	101	01000001	A
66	0x42	102	01000010	B
67	0x43	103	01000011	C
68	0x44	104	01000100	D
69	0x45	105	01000101	E
70	0x46	106	01000110	F
71	0x47	107	01000111	G
72	0x48	110	01001000	H
73	0x49	111	01001001	I
74	0x4A	112	01001010	J
75	0x4B	113	01001011	K
76	0x4C	114	01001100	L
77	0x4D	115	01001101	M
78	0x4E	116	01001110	N
79	0x4F	117	01001111	O
80	0x50	120	01010000	P
81	0x51	121	01010001	Q
82	0x52	122	01010010	R
83	0x53	123	01010011	S
84	0x54	124	01010100	T
85	0x55	125	01010101	U
86	0x56	126	01010110	V
87	0x57	127	01010111	W
88	0x58	130	01011000	X
89	0x59	131	01011001	Y
90	0x5A	132	01011010	Z
91	0x5B	133	01011011	[
92	0x5C	134	01011100	\
93	0x5D	135	01011101	]
94	0x5E	136	01011110	^
95	0x5F	137	01011111	_
96	0x60	140	01100000	`
97	0x61	141	01100001	a
98	0x62	142	01100010	b
99	0x63	143	01100011	c
100	0x64	144	01100100	d
101	0x65	145	01100101	e
102	0x66	146	01100110	f
103	0x67	147	01100111	g
104	0x68	150	01101000	h
105	0x69	151	01101001	i
106	0x6A	152	01101010	j
107	0x6B	153	01101011	k
108	0x6C	154	01101100	l
109	0x6D	155	01101101	m
110	0x6E	156	01101110	n
111	0x6F	157	01101111	o
112	0x70	160	01110000	p
113	0x71	161	01110001	q
114	0x72	162	01110010	r
115	0x73	163	01110011	s
116	0x74	164	01110100	t
117	0x75	165	01110101	u
118	0x76	166	01110110	v
119	0x77	167	01110111	w
120	0x78	170	01111000	x
121	0x79	171	01111001	y
122	0x7A	172	01111010	z
123	0x7B	173	01111011	{
124	0x7C	174	01111100	\|
125	0x7D	175	01111101	}
126	0x7E	176	01111110	~
127	0x7F	177	01111111	^?	DEL (Delete)

Text to ASCII

ASCII to Text

How to Use ASCII Table & Converter

Browse or search the ASCII reference table for any character.
Filter the table by control characters or printable characters.
Use the search to find a specific decimal, hex, or character value.
Type text in the Text to ASCII box to see its ASCII codes.
Enter ASCII codes in the ASCII to Text box to see the characters.
Click copy to save results to your clipboard.

Understanding ASCII Character Encoding

ASCII was developed by the American National Standards Institute (ANSI) and first published in 1963. It uses 7 bits to represent 128 unique characters, providing a standard way for computers to encode and exchange text. Every time you type on a keyboard, your computer internally stores each character as its ASCII (or Unicode) number.

The table is organized logically: codes 0-31 are control characters (non-printable), 32-47 are symbols and punctuation, 48-57 are digits 0-9, 58-64 are more symbols, 65-90 are uppercase A-Z, 91-96 are symbols, 97-122 are lowercase a-z, and 123-127 are symbols plus the DEL character.

A useful pattern: the difference between an uppercase letter and its lowercase equivalent is always 32 (one bit). In binary, 'A' (65) is 01000001 and 'a' (97) is 01100001 — only bit 5 differs. This property made case conversion extremely efficient on early hardware and is still used in optimized code today.

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