01000001. A is character 65, and 65 = 64 + 1, so only the bits worth 64 and 1 are on. Lowercase a is 01100001.

How do you write Hello in binary?

01001000 01100101 01101100 01101100 01101111: one 8-bit group for each of H, e, l, l, o. All-lowercase hello starts with 01101000 instead.

How do I convert binary to text?

Split the binary into groups of 8 bits, read each group as a number, and look up the character with that code. 01001000 01101001 is 72 and 105, which spells “Hi”. In the tool, press the switch button to change to Binary → text. It accepts groups separated by spaces, or one unbroken run whose length is a multiple of 8.

What is 255 in binary?

11111111, eight ones, the largest value that fits in one byte. It is FF in hexadecimal and 377 in octal. Use the Number bases tab for numbers: the text tab would encode the three characters 2, 5 and 5 instead.

Why do some characters give more than 8 bits?

UTF-8 uses one byte for ASCII characters and two to four bytes for everything else. é is two bytes (11000011 10101001), € is three and the emoji 😀 is four.

How are negative numbers and fractions handled?

A negative number keeps a minus sign, so −5 is shown as -101. The converter does not produce two’s complement and does not convert fractions.

Binary Converter

Convert text to binary and binary back to text in UTF-8: Hello is 01001000 01100101 01101100 01101100 01101111. A second tab converts whole numbers. How it works

Text → binary

Text

Binary (UTF-8)

01001000 01100101 01101100 01101100 01101111

Text is encoded as UTF-8 and shown as 8-bit groups: an ASCII letter is one group, é is two and an emoji is four. A lone surrogate half becomes U+FFFD. Binary back to text accepts groups separated by spaces, or one unbroken run whose length is a multiple of 8.

Reference: 0 to 16

The numbers 0 to 16 in decimal, binary, octal and hexadecimal
Decimal	Binary	Octal	Hex
0	0	0	0
1	1	1	1
2	10	2	2
3	11	3	3
4	100	4	4
5	101	5	5
6	110	6	6
7	111	7	7
8	1000	10	8
9	1001	11	9
10	1010	12	A
11	1011	13	B
12	1100	14	C
13	1101	15	D
14	1110	16	E
15	1111	17	F
16	10000	20	10

About the Binary Converter

The letter A is 01000001 in binary: its character code, 65, written in 8 bits. “Hi” is 01001000 01101001 and “Hello” is 01001000 01100101 01101100 01101100 01101111. This binary converter turns text into binary and binary back into text using UTF-8, and a second tab converts whole numbers between binary, decimal, octal and hexadecimal.

The alphabet in binary (8-bit codes)

Uppercase	Binary (uppercase)	Lowercase	Binary (lowercase)
A	01000001	a	01100001
B	01000010	b	01100010
C	01000011	c	01100011
D	01000100	d	01100100
E	01000101	e	01100101
F	01000110	f	01100110
G	01000111	g	01100111
H	01001000	h	01101000
I	01001001	i	01101001
J	01001010	j	01101010
K	01001011	k	01101011
L	01001100	l	01101100
M	01001101	m	01101101
N	01001110	n	01101110
O	01001111	o	01101111
P	01010000	p	01110000
Q	01010001	q	01110001
R	01010010	r	01110010
S	01010011	s	01110011
T	01010100	t	01110100
U	01010101	u	01110101
V	01010110	v	01110110
W	01010111	w	01110111
X	01011000	x	01111000
Y	01011001	y	01111001
Z	01011010	z	01111010

A lowercase letter differs from its capital in one bit, the third from the left, which is worth 32.

Digits and punctuation in binary

Digit	Binary (digit)	Character	Binary (character)
0	00110000	space	00100000
1	00110001	!	00100001
2	00110010	"	00100010
3	00110011	'	00100111
4	00110100	(	00101000
5	00110101	)	00101001
6	00110110	,	00101100
7	00110111	.	00101110
8	00111000	?	00111111
9	00111001	@	01000000

These are the codes of the characters. The number 5 is 101 in binary, but the character “5” in a piece of text is 00110101.

Words and symbols in binary

Text	Binary (UTF-8)
A	01000001
Hi	01001000 01101001
No	01001110 01101111
Yes	01011001 01100101 01110011
Hello	01001000 01100101 01101100 01101100 01101111
hello	01101000 01100101 01101100 01101100 01101111
I love you	01001001 00100000 01101100 01101111 01110110 01100101 00100000 01111001 01101111 01110101
é	11000011 10101001
€	11100010 10000010 10101100
😀	11110000 10011111 10011000 10000000

Common numbers in binary, octal and hexadecimal

Decimal	Binary	Octal	Hexadecimal
32	100000	40	20
64	1000000	100	40
100	1100100	144	64
127	1111111	177	7F
128	10000000	200	80
255	11111111	377	FF
256	100000000	400	100
1000	1111101000	1750	3E8
1024	10000000000	2000	400
65535	1111111111111111	177777	FFFF

From the Number bases tab, which is the same converter as the separate Number Base Converter page. The numbers 0 to 16 are listed in the reference table inside the tool.

Frequently asked questions

What is A in binary?: 01000001. A is character 65, and 65 = 64 + 1, so only the bits worth 64 and 1 are on. Lowercase a is 01100001.
How do you write Hello in binary?: 01001000 01100101 01101100 01101100 01101111: one 8-bit group for each of H, e, l, l, o. All-lowercase hello starts with 01101000 instead.
How do I convert binary to text?: Split the binary into groups of 8 bits, read each group as a number, and look up the character with that code. 01001000 01101001 is 72 and 105, which spells “Hi”. In the tool, press the switch button to change to Binary → text. It accepts groups separated by spaces, or one unbroken run whose length is a multiple of 8.
What is 255 in binary?: 11111111, eight ones, the largest value that fits in one byte. It is FF in hexadecimal and 377 in octal. Use the Number bases tab for numbers: the text tab would encode the three characters 2, 5 and 5 instead.
Why do some characters give more than 8 bits?: UTF-8 uses one byte for ASCII characters and two to four bytes for everything else. é is two bytes (11000011 10101001), € is three and the emoji 😀 is four.
How are negative numbers and fractions handled?: A negative number keeps a minus sign, so −5 is shown as -101. The converter does not produce two’s complement and does not convert fractions.

Reading and writing bytes as 0s and 1s

Count the 8-bit groups to see how many bytes a piece of text takes: an English letter, digit or space is one group, é two, € three and an emoji such as 😀 four. A capital and its lowercase letter differ in a single bit, worth 32, so A is 01000001 and a is 01100001. A string of 0s and 1s from a puzzle or a homework sheet decodes back to text when its length is a multiple of 8.

The Number bases tab rewrites one whole number between binary, octal, decimal and hexadecimal, which is how a bit mask, a file permission or a byte from a dump is usually read. It can also write the 0b, 0o or 0x prefix, as in 0xFF.

How text becomes binary

Text is encoded as UTF-8, and each byte is written as 8 binary digits with a space between bytes.

A → code 65 → 64 + 1 → 01000001

Example: Hi is 01001000 01101001, the codes 72 and 105.

Letters, digits and common punctuation are ASCII and take one byte each. Other characters take two to four bytes: é is 11000011 10101001, and the emoji 😀 is four groups.

Going back, the input is read 8 bits at a time and decoded as UTF-8. Groups may be separated by spaces or run together, as long as the total is a multiple of 8. A character other than 0 or 1, a group that is not 8 bits long, and bytes that are not valid UTF-8 are each reported with a message that says what is wrong.

The Number bases tab converts whole numbers: 255 is 11111111 in binary, 377 in octal and FF in hexadecimal. Negative numbers keep a minus sign (-5 is -101). Two's complement and fractions are not supported.

Fun Fact: UTF-8 was designed so that every ASCII character keeps its one-byte ASCII code (RFC 3629). That is why plain English text is the same string of bits in ASCII and in UTF-8.

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