ASCII Hex Table

How the table is arranged

ASCII is not an arbitrary list. Its layout was designed so that common operations became single bit manipulations, and the structure is still visible.

Hex range	Decimal	Contents
00–1F	0–31	Control characters
20	32	Space
21–2F	33–47	Punctuation and symbols
30–39	48–57	Digits 0–9
3A–40	58–64	More punctuation
41–5A	65–90	Capitals A–Z
5B–60	91–96	Brackets and symbols
61–7A	97–122	Lower case a–z
7B–7E	123–126	Braces and tilde
7F	127	Delete

Two design decisions still worth knowing

Digits start at 30, so the hex code for any digit is 3 followed by the digit itself — 37 is 7. And upper and lower case differ by exactly 20, a single bit, so changing case was historically one bitwise operation rather than a lookup.

Full ASCII table

All 128 codes. Control characters are named rather than rendered, because most of them have no visible form.

Hex	Decimal	Octal	Binary	Character
00	0	000	00000000	NUL null
01	1	001	00000001	SOH start of heading
02	2	002	00000010	STX start of text
03	3	003	00000011	ETX end of text
04	4	004	00000100	EOT end of transmission
05	5	005	00000101	ENQ enquiry
06	6	006	00000110	ACK acknowledge
07	7	007	00000111	BEL bell
08	8	010	00001000	BS backspace
09	9	011	00001001	HT horizontal tab
0A	10	012	00001010	LF line feed
0B	11	013	00001011	VT vertical tab
0C	12	014	00001100	FF form feed
0D	13	015	00001101	CR carriage return
0E	14	016	00001110	SO shift out
0F	15	017	00001111	SI shift in
10	16	020	00010000	DLE data link escape
11	17	021	00010001	DC1 device control 1
12	18	022	00010010	DC2 device control 2
13	19	023	00010011	DC3 device control 3
14	20	024	00010100	DC4 device control 4
15	21	025	00010101	NAK negative acknowledge
16	22	026	00010110	SYN synchronous idle
17	23	027	00010111	ETB end of block
18	24	030	00011000	CAN cancel
19	25	031	00011001	EM end of medium
1A	26	032	00011010	SUB substitute
1B	27	033	00011011	ESC escape
1C	28	034	00011100	FS file separator
1D	29	035	00011101	GS group separator
1E	30	036	00011110	RS record separator
1F	31	037	00011111	US unit separator
20	32	040	00100000	SP space
21	33	041	00100001	!
22	34	042	00100010	"
23	35	043	00100011	#
24	36	044	00100100	$
25	37	045	00100101	%
26	38	046	00100110	&
27	39	047	00100111	'
28	40	050	00101000	(
29	41	051	00101001	)
2A	42	052	00101010	*
2B	43	053	00101011	+
2C	44	054	00101100	,
2D	45	055	00101101	-
2E	46	056	00101110	.
2F	47	057	00101111	/
30	48	060	00110000	0
31	49	061	00110001	1
32	50	062	00110010	2
33	51	063	00110011	3
34	52	064	00110100	4
35	53	065	00110101	5
36	54	066	00110110	6
37	55	067	00110111	7
38	56	070	00111000	8
39	57	071	00111001	9
3A	58	072	00111010	:
3B	59	073	00111011	;
3C	60	074	00111100	<
3D	61	075	00111101	=
3E	62	076	00111110	>
3F	63	077	00111111	?
40	64	100	01000000	@
41	65	101	01000001	A
42	66	102	01000010	B
43	67	103	01000011	C
44	68	104	01000100	D
45	69	105	01000101	E
46	70	106	01000110	F
47	71	107	01000111	G
48	72	110	01001000	H
49	73	111	01001001	I
4A	74	112	01001010	J
4B	75	113	01001011	K
4C	76	114	01001100	L
4D	77	115	01001101	M
4E	78	116	01001110	N
4F	79	117	01001111	O
50	80	120	01010000	P
51	81	121	01010001	Q
52	82	122	01010010	R
53	83	123	01010011	S
54	84	124	01010100	T
55	85	125	01010101	U
56	86	126	01010110	V
57	87	127	01010111	W
58	88	130	01011000	X
59	89	131	01011001	Y
5A	90	132	01011010	Z
5B	91	133	01011011	[
5C	92	134	01011100	\
5D	93	135	01011101	]
5E	94	136	01011110	^
5F	95	137	01011111	_
60	96	140	01100000	`
61	97	141	01100001	a
62	98	142	01100010	b
63	99	143	01100011	c
64	100	144	01100100	d
65	101	145	01100101	e
66	102	146	01100110	f
67	103	147	01100111	g
68	104	150	01101000	h
69	105	151	01101001	i
6A	106	152	01101010	j
6B	107	153	01101011	k
6C	108	154	01101100	l
6D	109	155	01101101	m
6E	110	156	01101110	n
6F	111	157	01101111	o
70	112	160	01110000	p
71	113	161	01110001	q
72	114	162	01110010	r
73	115	163	01110011	s
74	116	164	01110100	t
75	117	165	01110101	u
76	118	166	01110110	v
77	119	167	01110111	w
78	120	170	01111000	x
79	121	171	01111001	y
7A	122	172	01111010	z
7B	123	173	01111011	{
7C	124	174	01111100	\|
7D	125	175	01111101	}
7E	126	176	01111110	~
7F	127	177	01111111	DEL delete

The control characters that still matter

Most of the first 32 codes were designed for teleprinters and are now historical. These six are not.

Hex	Name	Escape	Still used for
00	NUL	\\0	End of a C string; padding in binary formats
09	HT	\\t	Tab — indentation, TSV columns
0A	LF	\\n	Newline on Unix, macOS and in HTTP bodies
0D	CR	\\r	Paired with LF on Windows and in HTTP headers
1B	ESC	\\x1B	Opens a terminal escape sequence for color and cursor moves
7F	DEL		Originally punched-out tape; still sent by some keyboards

Seeing 0D 0A at every line ending tells you a file came from Windows or a network protocol. Seeing 0A alone tells you it did not. The decoded text looks identical either way; only the hex shows the difference.

Above 7F is not ASCII

ASCII defines 128 codes and stops. Anything from 80 upward belongs to some extension, and which extension changes the meaning entirely. The byte E9 is é in Latin-1 and the start of a three-byte sequence in UTF-8.

For anything modern, assume UTF-8 and use the hex to text converter, which decodes multi-byte characters correctly instead of guessing.

Frequently asked questions

What is 41 in ASCII?

Capital A. Lower case a is 61, exactly 20 hex higher, because case differs by a single bit.

What is the ASCII code for space?

32 decimal, which is 20 in hex. It is a real byte.

How many characters does ASCII define?

128, numbered 0 to 127. Codes 0 to 31 and 127 are control characters rather than printable.

Why do digits start at hex 30?

So the hex code for a digit is 3 followed by the digit itself. It made converting between a character and its numeric value trivial.

What are the codes above 127?

Not ASCII. They belong to an extension such as Latin-1 or UTF-8, and you must know which one to decode them correctly.

What is the difference between CR and LF?

LF is 0A and ends a line on Unix and macOS. CR is 0D, and Windows and HTTP headers use CR followed by LF.

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