ASCII Reference

The complete 7-bit character set, its control codes, printable characters, and common relationships.

Updated 2026-07-22

Overview

ASCII is a 7-bit character encoding containing 128 code points numbered 0 through 127. It was designed for information interchange and remains the common foundation of many modern text encodings.

The first 32 values and value 127 are control characters. Values 32 through 126 are printable characters. Unicode preserves this range as U+0000 through U+007F, and UTF-8 represents it with the same single-byte values.

Code Ranges

Category	Decimal	Hexadecimal	Description
C0 controls	0–31	00–1F	Control characters
Space	32	20	First printable character
Digits	48–57	30–39	Characters 0 through 9
Uppercase letters	65–90	41–5A	Characters A through Z
Lowercase letters	97–122	61–7A	Characters a through z
Printable characters	32–126	20–7E	Space through tilde
Delete	127	7F	DEL control character

Control Characters

Control characters do not represent ordinary printable glyphs. Their original purposes included controlling terminals, data links, printers, and record-oriented data streams. Some, including tab, line feed, carriage return, escape, and delete, remain common.

Binary	Octal	Decimal	Hex	Unicode	Abbr.	Picture	Caret	Escape	Name
0000000	000	0	00	U+0000	NUL	␀	^@	\0	Null
0000001	001	1	01	U+0001	SOH	␁	^A		Start of Heading
0000010	002	2	02	U+0002	STX	␂	^B		Start of Text
0000011	003	3	03	U+0003	ETX	␃	^C		End of Text
0000100	004	4	04	U+0004	EOT	␄	^D		End of Transmission
0000101	005	5	05	U+0005	ENQ	␅	^E		Enquiry
0000110	006	6	06	U+0006	ACK	␆	^F		Acknowledgement
0000111	007	7	07	U+0007	BEL	␇	^G	\a	Bell
0001000	010	8	08	U+0008	BS	␈	^H	\b	Backspace
0001001	011	9	09	U+0009	HT	␉	^I	\t	Horizontal Tab
0001010	012	10	0A	U+000A	LF	␊	^J	\n	Line Feed
0001011	013	11	0B	U+000B	VT	␋	^K	\v	Vertical Tab
0001100	014	12	0C	U+000C	FF	␌	^L	\f	Form Feed
0001101	015	13	0D	U+000D	CR	␍	^M	\r	Carriage Return
0001110	016	14	0E	U+000E	SO	␎	^N		Shift Out
0001111	017	15	0F	U+000F	SI	␏	^O		Shift In
0010000	020	16	10	U+0010	DLE	␐	^P		Data Link Escape
0010001	021	17	11	U+0011	DC1	␑	^Q		Device Control 1 (often XON)
0010010	022	18	12	U+0012	DC2	␒	^R		Device Control 2
0010011	023	19	13	U+0013	DC3	␓	^S		Device Control 3 (often XOFF)
0010100	024	20	14	U+0014	DC4	␔	^T		Device Control 4
0010101	025	21	15	U+0015	NAK	␕	^U		Negative Acknowledgement
0010110	026	22	16	U+0016	SYN	␖	^V		Synchronous Idle
0010111	027	23	17	U+0017	ETB	␗	^W		End of Transmission Block
0011000	030	24	18	U+0018	CAN	␘	^X		Cancel
0011001	031	25	19	U+0019	EM	␙	^Y		End of Medium
0011010	032	26	1A	U+001A	SUB	␚	^Z		Substitute
0011011	033	27	1B	U+001B	ESC	␛	^[	\x1B	Escape
0011100	034	28	1C	U+001C	FS	␜	^\		File Separator
0011101	035	29	1D	U+001D	GS	␝	^]		Group Separator
0011110	036	30	1E	U+001E	RS	␞	^^		Record Separator
0011111	037	31	1F	U+001F	US	␟	^_		Unit Separator
1111111	177	127	7F	U+007F	DEL	␡	^?		Delete

Printable Characters

Binary	Octal	Decimal	Hex	Unicode	Glyph
0100000	040	32	20	U+0020	SP
0100001	041	33	21	U+0021	!
0100010	042	34	22	U+0022	"
0100011	043	35	23	U+0023	#
0100100	044	36	24	U+0024	$
0100101	045	37	25	U+0025	%
0100110	046	38	26	U+0026	&
0100111	047	39	27	U+0027	'
0101000	050	40	28	U+0028	(
0101001	051	41	29	U+0029	)
0101010	052	42	2A	U+002A	*
0101011	053	43	2B	U+002B	+
0101100	054	44	2C	U+002C	,
0101101	055	45	2D	U+002D	-
0101110	056	46	2E	U+002E	.
0101111	057	47	2F	U+002F	/
0110000	060	48	30	U+0030	0
0110001	061	49	31	U+0031	1
0110010	062	50	32	U+0032	2
0110011	063	51	33	U+0033	3
0110100	064	52	34	U+0034	4
0110101	065	53	35	U+0035	5
0110110	066	54	36	U+0036	6
0110111	067	55	37	U+0037	7
0111000	070	56	38	U+0038	8
0111001	071	57	39	U+0039	9
0111010	072	58	3A	U+003A	:
0111011	073	59	3B	U+003B	;
0111100	074	60	3C	U+003C	<
0111101	075	61	3D	U+003D	=
0111110	076	62	3E	U+003E	>
0111111	077	63	3F	U+003F	?
1000000	100	64	40	U+0040	@
1000001	101	65	41	U+0041	A
1000010	102	66	42	U+0042	B
1000011	103	67	43	U+0043	C
1000100	104	68	44	U+0044	D
1000101	105	69	45	U+0045	E
1000110	106	70	46	U+0046	F
1000111	107	71	47	U+0047	G
1001000	110	72	48	U+0048	H
1001001	111	73	49	U+0049	I
1001010	112	74	4A	U+004A	J
1001011	113	75	4B	U+004B	K
1001100	114	76	4C	U+004C	L
1001101	115	77	4D	U+004D	M
1001110	116	78	4E	U+004E	N
1001111	117	79	4F	U+004F	O
1010000	120	80	50	U+0050	P
1010001	121	81	51	U+0051	Q
1010010	122	82	52	U+0052	R
1010011	123	83	53	U+0053	S
1010100	124	84	54	U+0054	T
1010101	125	85	55	U+0055	U
1010110	126	86	56	U+0056	V
1010111	127	87	57	U+0057	W
1011000	130	88	58	U+0058	X
1011001	131	89	59	U+0059	Y
1011010	132	90	5A	U+005A	Z
1011011	133	91	5B	U+005B	[
1011100	134	92	5C	U+005C	\
1011101	135	93	5D	U+005D	]
1011110	136	94	5E	U+005E	^
1011111	137	95	5F	U+005F	_
1100000	140	96	60	U+0060	`
1100001	141	97	61	U+0061	a
1100010	142	98	62	U+0062	b
1100011	143	99	63	U+0063	c
1100100	144	100	64	U+0064	d
1100101	145	101	65	U+0065	e
1100110	146	102	66	U+0066	f
1100111	147	103	67	U+0067	g
1101000	150	104	68	U+0068	h
1101001	151	105	69	U+0069	i
1101010	152	106	6A	U+006A	j
1101011	153	107	6B	U+006B	k
1101100	154	108	6C	U+006C	l
1101101	155	109	6D	U+006D	m
1101110	156	110	6E	U+006E	n
1101111	157	111	6F	U+006F	o
1110000	160	112	70	U+0070	p
1110001	161	113	71	U+0071	q
1110010	162	114	72	U+0072	r
1110011	163	115	73	U+0073	s
1110100	164	116	74	U+0074	t
1110101	165	117	75	U+0075	u
1110110	166	118	76	U+0076	v
1110111	167	119	77	U+0077	w
1111000	170	120	78	U+0078	x
1111001	171	121	79	U+0079	y
1111010	172	122	7A	U+007A	z
1111011	173	123	7B	U+007B	{
1111100	174	124	7C	U+007C	\|
1111101	175	125	7D	U+007D	}
1111110	176	126	7E	U+007E	~

Useful Relationships

The numeric value of an ASCII digit is its code minus 48 (0x30).
Matching uppercase and lowercase letters differ by 32 (0x20).
For ASCII letters only, setting the 0x20 bit converts A–Z to lowercase.
For ASCII letters only, clearing the 0x20 bit converts a–z to uppercase.
Unix-like systems use LF for line endings; Windows conventionally uses CR followed by LF.

CSS

printf '%d 0x%X\n' "'A" "'A"
printf '%d 0x%X\n' "'a" "'a"

History and Modern Use

ASCII was standardized during the 1960s and revised over time. Some character positions and names differed between early editions, which explains historical glyph variants found in older tables and equipment.

Today ASCII is most often encountered as the shared subset of Unicode and UTF-8, in programming-language syntax, network protocols, terminal controls, and plain-text file formats.

ASCII Reference

ASCII Reference

Overview

Code Ranges

Control Characters

Printable Characters

Useful Relationships

History and Modern Use

Description

References

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