Text to Binary Converter - Binary, Hex, Octal, Decimal and Back

Type text and see the bytes behind it in binary, hexadecimal, octal or decimal, or paste bytes and read the text they spell.

Maintained by Hirantha Sandaruwan Lakshan. Updated 13 October 2026.

About this tool

The conversion uses UTF-8, the encoding of almost every web page, so the letter A is one byte (01000001) and the letter é is two (11000011 10101001). Mistakes in pasted code are reported with their position instead of being quietly repaired. It all runs in your browser and nothing is sent anywhere.

How it works

How to read binary. A byte is eight bits, and each bit is worth a power of two: 128, 64, 32, 16, 8, 4, 2, 1 from left to right. Add up the places that hold a 1. The byte 01000001 has a 1 in the 64 place and the 1 place, so it is 65, which is the letter A. The two bytes 01001000 01101001 are 72 and 105, the letters H and i, so together they spell Hi. Hexadecimal writes the same byte with two digits (41 for 65; 48 69 for Hi), octal with up to three (101) and decimal as a number from 0 to 255.

From text to bytes. The text is cut into characters and each is stored in UTF-8, defined in RFC 3629. A character from U+0000 to U+007F takes one byte and is identical to ASCII. U+0080 to U+07FF takes two bytes, U+0800 to U+FFFF three, and U+10000 to U+10FFFF four. So the letter é (U+00E9) is C3 A9, the euro sign (U+20AC) is E2 82 AC, and the grinning face emoji (U+1F600) is F0 9F 98 80. This tool uses the browser's own TextEncoder, which always produces UTF-8, and lists the first 64 characters one by one so you can see which bytes belong to which character.

From bytes to text. Your groups are read as bytes and then checked against the well-formed UTF-8 sequences before any text is built. Separate the groups with spaces, commas, semicolons or line breaks; each may start with 0b, 0x or 0o. Without separators binary is read eight digits at a time, hexadecimal two and octal three, while decimal needs separators. A digit that does not belong, a group of the wrong length or a decimal over 255 is reported with its group number, line and column. Bytes that are not valid UTF-8, such as a lone C3, are reported with the byte position. They are never swapped for the replacement character, so a mistake cannot hide.

ASCII is the older 7-bit code of 128 values: 33 control codes and 95 printable characters, from the space (32) to the tilde (126). The table on this page lists all 95 in decimal, hexadecimal, octal and binary. Values 128 to 255 are not ASCII, and what they mean depends on the encoding (Latin-1 and Windows-1252 differ), so a byte in that range is accepted here only as part of a valid UTF-8 sequence.

Worked examples

The letter A

A is code 65. Since 65 = 64 + 1, the byte is 01000001 in binary, 41 in hexadecimal, 101 in octal and 65 in decimal. Lower-case a is 97, which is 01100001: the only change is the 32 place.

The word Hi

H is 72 (01001000) and i is 105 (01101001), so Hi is 01001000 01101001 in binary and 48 69 in hexadecimal. Paste either back in Code to text mode and you get Hi.

A letter with an accent

The letter é is U+00E9, which UTF-8 stores in two bytes: 11000011 10101001, or C3 A9 in hexadecimal. The first byte starts with 110 (a two-byte character) and the second with 10 (a continuation byte). A converter that gives one byte for é is using Latin-1, not UTF-8.

Finding a typo in pasted binary

In 01001000 01101002 the last digit is a 2. The tool says group 2 (line 1, column 17) has a character that is not a binary digit, and leaves the rest alone so you can fix just that digit.

Printable ASCII characters (32 to 126)

Character	Decimal	Hex	Octal	Binary
space	32	20	040	00100000
!	33	21	041	00100001
"	34	22	042	00100010
#	35	23	043	00100011
$	36	24	044	00100100
%	37	25	045	00100101
&	38	26	046	00100110
'	39	27	047	00100111
(	40	28	050	00101000
)	41	29	051	00101001
*	42	2A	052	00101010
+	43	2B	053	00101011
,	44	2C	054	00101100
-	45	2D	055	00101101
.	46	2E	056	00101110
/	47	2F	057	00101111
0	48	30	060	00110000
1	49	31	061	00110001
2	50	32	062	00110010
3	51	33	063	00110011
4	52	34	064	00110100
5	53	35	065	00110101
6	54	36	066	00110110
7	55	37	067	00110111
8	56	38	070	00111000
9	57	39	071	00111001
:	58	3A	072	00111010
;	59	3B	073	00111011
<	60	3C	074	00111100
=	61	3D	075	00111101
>	62	3E	076	00111110
?	63	3F	077	00111111
@	64	40	100	01000000
A	65	41	101	01000001
B	66	42	102	01000010
C	67	43	103	01000011
D	68	44	104	01000100
E	69	45	105	01000101
F	70	46	106	01000110
G	71	47	107	01000111
H	72	48	110	01001000
I	73	49	111	01001001
J	74	4A	112	01001010
K	75	4B	113	01001011
L	76	4C	114	01001100
M	77	4D	115	01001101
N	78	4E	116	01001110
O	79	4F	117	01001111
P	80	50	120	01010000
Q	81	51	121	01010001
R	82	52	122	01010010
S	83	53	123	01010011
T	84	54	124	01010100
U	85	55	125	01010101
V	86	56	126	01010110
W	87	57	127	01010111
X	88	58	130	01011000
Y	89	59	131	01011001
Z	90	5A	132	01011010
[	91	5B	133	01011011
\	92	5C	134	01011100
]	93	5D	135	01011101
^	94	5E	136	01011110
_	95	5F	137	01011111
`	96	60	140	01100000
a	97	61	141	01100001
b	98	62	142	01100010
c	99	63	143	01100011
d	100	64	144	01100100
e	101	65	145	01100101
f	102	66	146	01100110
g	103	67	147	01100111
h	104	68	150	01101000
i	105	69	151	01101001
j	106	6A	152	01101010
k	107	6B	153	01101011
l	108	6C	154	01101100
m	109	6D	155	01101101
n	110	6E	156	01101110
o	111	6F	157	01101111
p	112	70	160	01110000
q	113	71	161	01110001
r	114	72	162	01110010
s	115	73	163	01110011
t	116	74	164	01110100
u	117	75	165	01110101
v	118	76	166	01110110
w	119	77	167	01110111
x	120	78	170	01111000
y	121	79	171	01111001
z	122	7A	172	01111010
{	123	7B	173	01111011
\|	124	7C	174	01111100
}	125	7D	175	01111101
~	126	7E	176	01111110

Frequently asked questions

How do I convert text to binary?

Turn each character into its UTF-8 bytes, then write each byte as eight binary digits. For Hi the bytes are 72 and 105, which are 01001000 and 01101001. The converter does this as you type and lets you choose the separator, 4-bit grouping and a 0b prefix.

What is the binary code for the letter A?

Capital A is 01000001 (decimal 65, hexadecimal 41). Lower-case a is 01100001 (97, 61). Letters, digits and punctuation all have fixed codes; the table on this page lists the 95 printable ASCII characters.

Why does é turn into two bytes but e into one?

UTF-8 uses one byte for the 128 ASCII characters and more bytes for the rest of Unicode: two for accented Latin letters, Greek, Cyrillic, Hebrew and Arabic, three for most other scripts including Sinhala and Tamil, and four for characters above U+FFFF such as most emoji. The first byte tells a reader how many bytes follow.

Is this ASCII or Unicode?

Both, in the sense that matters. ASCII is the first 128 Unicode characters, and UTF-8 stores them as the same single bytes. Text that is plain English therefore gives the same bytes in ASCII and in UTF-8. The two differ only for characters outside ASCII.

How do I convert binary back to text?

Choose Code to text, pick Binary and paste the bytes with a space between each group of eight digits. Groups of four digits (0100 1000) are also understood and are joined in pairs. If a group has seven digits the tool shows you the padded version to use, for example 01000001 for 1000001.

What does it mean when the bytes are not valid UTF-8?

Some byte patterns can never appear in UTF-8: a continuation byte with no lead byte, a lead byte whose follower is missing, or the overlong forms C0 and C1. A common cause is text saved in Latin-1, where é is the single byte E9. In UTF-8 E9 starts a three-byte character, so it fails. The tool reports the byte position and keeps the bytes as they are.

Is my text uploaded anywhere?

No. The conversion runs in your browser with its built-in TextEncoder and TextDecoder, and nothing you type is sent to a server.

Sources & references

Updated Oct 13, 2026