ASCII table

A computer does not store letters, it stores numbers. ASCII decides which number stands for which character, and has done since 1963. There are 128 characters, the numbers 0 to 127, so each one fits in a byte.

Every row below is one character. On the left is the number in decimal, next to it the same number in hexadecimal and in binary, and on the right the character itself. If a puzzle hands you 72 105, look them up here and you read H and i. Hex values are often written with 0x in front, so 0x41 is A.

The first 32 codes and 127 are control characters. You cannot see them. They used to drive teleprinters and still do things like a line break (LF, 10) or a tab (HT, 9). The table shows their short names instead, and the space (32) is shown as SP.

Upper and lower case letters are exactly 32 apart: A is 65, a is 97. In binary that is a single bit, which is why they sit side by side in the wide view. The digits start at 48, so 0 is 48 and 9 is 57.

Dec	Hex	Binary	Char
0	00	00000000	NUL
1	01	00000001	SOH
2	02	00000010	STX
3	03	00000011	ETX
4	04	00000100	EOT
5	05	00000101	ENQ
6	06	00000110	ACK
7	07	00000111	BEL
8	08	00001000	BS
9	09	00001001	HT
10	0A	00001010	LF
11	0B	00001011	VT
12	0C	00001100	FF
13	0D	00001101	CR
14	0E	00001110	SO
15	0F	00001111	SI
16	10	00010000	DLE
17	11	00010001	DC1
18	12	00010010	DC2
19	13	00010011	DC3
20	14	00010100	DC4
21	15	00010101	NAK
22	16	00010110	SYN
23	17	00010111	ETB
24	18	00011000	CAN
25	19	00011001	EM
26	1A	00011010	SUB
27	1B	00011011	ESC
28	1C	00011100	FS
29	1D	00011101	GS
30	1E	00011110	RS
31	1F	00011111	US

Dec	Hex	Binary	Char
32	20	00100000	SP
33	21	00100001	!
34	22	00100010	"
35	23	00100011	#
36	24	00100100	$
37	25	00100101	%
38	26	00100110	&
39	27	00100111	'
40	28	00101000	(
41	29	00101001	)
42	2A	00101010	*
43	2B	00101011	+
44	2C	00101100	,
45	2D	00101101	-
46	2E	00101110	.
47	2F	00101111	/
48	30	00110000	0
49	31	00110001	1
50	32	00110010	2
51	33	00110011	3
52	34	00110100	4
53	35	00110101	5
54	36	00110110	6
55	37	00110111	7
56	38	00111000	8
57	39	00111001	9
58	3A	00111010	:
59	3B	00111011	;
60	3C	00111100	<
61	3D	00111101	=
62	3E	00111110	>
63	3F	00111111	?

Dec	Hex	Binary	Char
64	40	01000000	@
65	41	01000001	A
66	42	01000010	B
67	43	01000011	C
68	44	01000100	D
69	45	01000101	E
70	46	01000110	F
71	47	01000111	G
72	48	01001000	H
73	49	01001001	I
74	4A	01001010	J
75	4B	01001011	K
76	4C	01001100	L
77	4D	01001101	M
78	4E	01001110	N
79	4F	01001111	O
80	50	01010000	P
81	51	01010001	Q
82	52	01010010	R
83	53	01010011	S
84	54	01010100	T
85	55	01010101	U
86	56	01010110	V
87	57	01010111	W
88	58	01011000	X
89	59	01011001	Y
90	5A	01011010	Z
91	5B	01011011	[
92	5C	01011100	\
93	5D	01011101	]
94	5E	01011110	^
95	5F	01011111	_

Dec	Hex	Binary	Char
96	60	01100000	`
97	61	01100001	a
98	62	01100010	b
99	63	01100011	c
100	64	01100100	d
101	65	01100101	e
102	66	01100110	f
103	67	01100111	g
104	68	01101000	h
105	69	01101001	i
106	6A	01101010	j
107	6B	01101011	k
108	6C	01101100	l
109	6D	01101101	m
110	6E	01101110	n
111	6F	01101111	o
112	70	01110000	p
113	71	01110001	q
114	72	01110010	r
115	73	01110011	s
116	74	01110100	t
117	75	01110101	u
118	76	01110110	v
119	77	01110111	w
120	78	01111000	x
121	79	01111001	y
122	7A	01111010	z
123	7B	01111011	{
124	7C	01111100	\|
125	7D	01111101	}
126	7E	01111110	~
127	7F	01111111	DEL