Reference chart

Binary Alphabet Chart

Every letter and digit as the 8-bit byte a computer stores, using the ASCII codes reproduced in RFC 20. These bytes are identical in UTF-8, the encoding used by most of the web (RFC 3629).

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CodeShift · codeshift.pages.dev/binary-alphabet/

Uppercase A–Z

Letter	Binary	Decimal
A	01000001	65
B	01000010	66
C	01000011	67
D	01000100	68
E	01000101	69
F	01000110	70
G	01000111	71
H	01001000	72
I	01001001	73
J	01001010	74
K	01001011	75
L	01001100	76
M	01001101	77
N	01001110	78
O	01001111	79
P	01010000	80
Q	01010001	81
R	01010010	82
S	01010011	83
T	01010100	84
U	01010101	85
V	01010110	86
W	01010111	87
X	01011000	88
Y	01011001	89
Z	01011010	90

Lowercase a–z

Letter	Binary	Decimal
a	01100001	97
b	01100010	98
c	01100011	99
d	01100100	100
e	01100101	101
f	01100110	102
g	01100111	103
h	01101000	104
i	01101001	105
j	01101010	106
k	01101011	107
l	01101100	108
m	01101101	109
n	01101110	110
o	01101111	111
p	01110000	112
q	01110001	113
r	01110010	114
s	01110011	115
t	01110100	116
u	01110101	117
v	01110110	118
w	01110111	119
x	01111000	120
y	01111001	121
z	01111010	122

Digits 0–9 and space

000110000decimal 48

100110001decimal 49

200110010decimal 50

300110011decimal 51

400110100decimal 52

500110101decimal 53

600110110decimal 54

700110111decimal 55

800111000decimal 56

900111001decimal 57

space00100000decimal 32

How to read a binary letter

Each byte has eight bits. From left to right they are worth 128, 64, 32, 16, 8, 4, 2 and 1; add up the positions that hold a 1. Capital A, 01000001, has 1s in the 64 and 1 positions: 64 + 1 = 65. Capital letters run from 65 to 90, lowercase from 97 to 122, and the digits from 48 to 57 — so the digit 7 is not stored as 7 but as 55 (00110111).

The one-bit case switch

Compare A (01000001) with a (01100001): only the bit worth 32 differs. That holds for every letter, a deliberate feature of ASCII that makes converting case a single bit operation. Accented letters and emoji are not in this table; in UTF-8 they take two to four bytes each — the binary translator shows them byte by byte.

For the full set of 128 codes, including punctuation and control characters, see the ASCII table.

Sources

Frequently asked questions

What is A in binary?+

Capital A is 01000001 (decimal 65); lowercase a is 01100001 (decimal 97).

Why do capital and lowercase letters differ by one bit?+

In ASCII every lowercase letter is exactly 32 more than its capital, and 32 is a single bit (the third bit from the left in an 8-bit byte), so flipping that bit switches case.

What is a space in binary?+

A space is 00100000 (decimal 32).

Translate with it

Binary Translator

Text ↔ 8-bit binary (UTF-8), spaces optional.

Other charts

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