Binary Alphabet: A to Z in Binary Code (Capital and Lowercase)

The short answer

In binary code, capital A is 01000001 and lowercase a is 01100001. Every letter is stored as its ASCII number written in 8 bits: A to Z run from 65 to 90 (01000001 to 01011010) and a to z run from 97 to 122 (01100001 to 01111010). The full chart is below, and the Binary Code Translator converts any word or sentence to binary, and binary back to text, as you type.

Binary alphabet: capital letters A to Z

Each code below is the letter's ASCII decimal value converted to base 2 and padded to 8 digits. The values were generated with the same method the translator uses.

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

Binary alphabet: lowercase letters a to z

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

Numbers, space and punctuation

Digits are characters too, so "7" as text is not the same as the number seven in binary.

Character	Decimal	Binary
space	32	00100000
!	33	00100001
.	46	00101110
0	48	00110000
1	49	00110001
2	50	00110010
5	53	00110101
7	55	00110111
9	57	00111001
?	63	00111111

The digits 0 to 9 run in order from 00110000 to 00111001, so the last four bits of each digit are the digit itself in binary. The number seven is 111, and the character "7" is 0011 followed by 0111.

Patterns that make the chart easy to remember

You do not need to memorise 52 codes. Three patterns cover the whole alphabet:

• Capitals start with 010. Every code from A to Z begins 010, and the last five bits count the letter's position: A is 00001 (1), B is 00010 (2), and Z is 11010 (26).
• Lowercase starts with 011. The last five bits are the same as the capital. So a is 011 + 00001 and z is 011 + 11010.
• Capital and lowercase differ by one bit. The third bit from the left is 0 for capitals and 1 for lowercase. In decimal that bit is worth 32, which is why a (97) is exactly 32 more than A (65).

So to write any letter in binary, find its position in the alphabet, write that number in 5 bits and put 010 (capital) or 011 (lowercase) in front.

Example: the letter K. K is the 11th letter. 11 in 5 bits is 01011. Capital K is 010 01011 = 01001011. Lowercase k is 011 01011 = 01101011. Both match the tables.

Words in binary: worked examples

Letters are written in order with a space between each 8-bit group. These outputs come from the translator:

• Hi → 01001000 01101001
• HELLO → 01001000 01000101 01001100 01001100 01001111
• I love you → 01001001 00100000 01101100 01101111 01110110 01100101 00100000 01111001 01101111 01110101

Notice the 00100000 groups in the last example. Those are the spaces between words. Leave them out and the decoded text runs together as "Iloveyou".

How to convert text to binary with the translator

Open the Binary Code Translator.

Choose Text → Binary.

Type or paste your text. The binary output updates as you type.

Use Copy next to the output you need. In this mode the tool also shows the Hexadecimal and Decimal (ASCII) codes for the same text, which is handy for checking a chart like the one above.

To go the other way, choose Binary → Text and paste 8-bit groups separated by spaces. The translator reads each group as one character. A group it cannot read as binary shows as a question mark.

What about accented letters, rupee signs and emoji?

The chart above covers the basic English letters, which are identical in ASCII, Unicode and UTF-8. Outside that range, results depend on which encoding a converter uses, so two tools can disagree.

The Lazyblink translator converts each character's JavaScript character code (UTF-16) to binary. For example:

• é becomes 11101001 (decimal 233). A converter that uses UTF-8 bytes would show two bytes instead: 11000011 10101001.
• ₹ becomes a single 14-digit group, 10000010111001, because its code (8377) does not fit in 8 bits.
• An emoji such as 😀 becomes two 16-digit groups, because UTF-16 stores it as a pair of codes.

Text converted with this tool decodes correctly with this tool. If you need to match a specific system that expects UTF-8 bytes, stick to plain English letters, digits and common punctuation, or use a converter that states it outputs UTF-8.

Common mistakes

• Dropping the leading zero. A is 01000001, not 1000001. Both have the same value, but most binary puzzles and decoders expect 8-bit groups, and missing zeros shift everything if you remove the spaces.
• Removing the spaces between groups. The decoder splits on spaces. A continuous string of 0s and 1s cannot be split back into letters by this tool.
• Mixing up capital and lowercase. "hello" and "HELLO" give different binary. Check the third bit.
• Confusing the digit with the number. The character "5" is 00110101. The number five in binary is 101.
• Treating binary as encryption. Anyone can decode it in seconds. It is fine for puzzles, gifts and lessons, not for secrets.

Ideas for using the binary alphabet

• Write a name in binary for a bracelet, card or T-shirt design. Each letter is one bead or block of eight.
• Set a classroom puzzle: give students the three patterns above and ask them to decode a short word without the chart.
• Check homework answers by pasting the student's binary into Binary → Text mode.

Related tools and guides

• A step-by-step method for converting text to binary by hand, and back: How to Convert Text to Binary
• Another way to turn text into a string of safe characters (also not encryption): Base64 Encoder and Decoder