ToolNestLetter to Binary Converter A to Z Chart
A letter to binary converter turns each letter into its 8-bit binary code: A is 01000001, B is 01000010, and a is 01100001. Every letter has one fixed code, set by the ASCII standard. Convert any text instantly with our free text to binary converter.
The A to Z Chart: Uppercase Letters in Binary
The uppercase alphabet in 8-bit binary runs from A = 01000001 through Z = 01011010, and the pattern is the reason the chart is easy to memorize in chunks. A is 65 in decimal, B is 66, and each following letter adds one, so the binary counts upward in step: C is 01000011, D is 01000100, E is 01000101, and so on through M = 01001101, N = 01001110, and Z = 01011010. The first three bits are always 010 for uppercase letters, which is why every uppercase code starts with the same prefix and only the last five bits change. That prefix is not a coincidence: ASCII assigns the uppercase letters the decimal range 65 to 90, and 64 is 01000000 in binary, so each letter is 64 plus its position in the alphabet, with A as position 1. Reading the chart this way turns a lookup table into a rule: take the letter's position, add 64, and write the result in 8-bit binary. The full uppercase list is A 01000001, B 01000010, C 01000011, D 01000100, E 01000101, F 01000110, G 01000111, H 01001000, I 01001001, J 01001010, K 01001011, L 01001100, M 01001101, N 01001110, O 01001111, P 01010000, Q 01010001, R 01010010, S 01010011, T 01010100, U 01010101, V 01010110, W 01010111, X 01011000, Y 01011001, Z 01011010.
The A to Z Chart: Lowercase Letters in Binary
Lowercase letters follow the same rule with a different base: a is 97 in decimal, written 01100001, and the codes run upward to z = 01111010. The prefix for lowercase is 011 instead of 010, and the last five bits repeat the uppercase pattern exactly, because lowercase a is exactly 32 more than uppercase A in every encoding that descends from ASCII. That 32-offset is the single most useful fact in the whole chart: to change case, flip the sixth bit, or equivalently add or subtract 32 from the decimal value. So a = 01100001, b = 01100010, c = 01100011, d = 01100100, e = 01100101, f = 01100110, g = 01100111, h = 01101000, i = 01101001, j = 01101010, k = 01101011, l = 01101100, m = 01101101, n = 01101110, o = 01101111, p = 01110000, q = 01110001, r = 01110010, s = 01110011, t = 01110100, u = 01110101, v = 01110110, w = 01110111, x = 01111000, y = 01111001, z = 01111010. Typing a sentence through a text to binary converter shows this pattern live: the same letter in upper and lower case differs in exactly one bit position, which is why case conversion is one of the cheapest operations a computer performs.
7-Bit vs 8-Bit: Which Chart Should You Use?
Original ASCII is a 7-bit code, which means A is 1000001 and a is 1100001, with no leading zero. Modern systems almost always show 8-bit bytes instead, padding the 7-bit code with a leading zero to make A = 01000001 and a = 01100001. The two forms describe the same letter; the extra zero is padding, not information, and it exists because computers store data in 8-bit bytes. Confusion arises when a chart drops the leading zero and a reader counts only seven bits, or when a chart shows 8 bits and a reader expects 7. The rule: if you are writing binary for a computer, a file, or a converter, use 8 bits per letter. If you are studying the history of ASCII or reading an old textbook, expect 7 bits. Either way, the decimal values are identical — A is 65, a is 97 — and only the presentation differs. Unicode extends the same idea far beyond ASCII: the first 128 Unicode code points are ASCII itself, so every letter in this chart keeps its code in UTF-8, and accented or non-Latin letters get longer codes that a plain ASCII chart does not cover. For text beyond A to Z, a converter that handles full Unicode is the right tool, not a longer ASCII table.
How to Convert a Letter to Binary by Hand
Converting by hand takes three steps and no memorization beyond powers of two. Step one: find the decimal value, either from the chart or from the alphabet rule — uppercase is 64 plus position, lowercase is 96 plus position, so K, the 11th letter, is 75 uppercase and 107 lowercase. Step two: break the decimal into powers of two, 128, 64, 32, 16, 8, 4, 2, 1, writing 1 where a power fits and 0 where it does not. For K = 75: 64 fits (remainder 11), 32 does not, 16 does not, 8 fits (remainder 3), 4 does not, 2 fits (remainder 1), 1 fits, giving 01001011. Step three: pad to 8 bits if your result is shorter, which the leading zero already handles for all letters, since no letter exceeds 122. Try it with a second letter to lock the method: lowercase m is 109, and 64 + 32 + 8 + 4 + 1 = 109, so the bits are 01101101, matching the chart. The reverse trip is just as mechanical: read each 1 bit as its power of two and add them, so 01010011 becomes 64 + 16 + 2 + 1 = 83, which is S. A binary to text converter runs the reverse trip for whole messages, which is how encoded text becomes readable again.
Words in Binary: Spacing, Punctuation, and Examples
Single letters are the building blocks; words are the same blocks joined with a space character, which is 00100000, decimal 32. The word Hi in binary is 01001000 01101001, with a space between the two letter codes that is only a visual separator, not part of the data. The word Cat is 01000011 01100001 01110100, and the word dog is 01100100 01101111 01100111, where the lowercase prefix 011 marks every letter. Punctuation has codes too: a period is 00101110, a comma is 00101100, an exclamation mark is 00100001, and a question mark is 00111111. Digits are their own range, 0 = 00110000 through 9 = 00111001, which is why the digit 1 is not the same as the number 1 in a computer — the digit is a character with code 49, while the number is a value stored differently. A full sentence therefore converts letter by letter, space by space, and punctuation by punctuation, and the result looks long because each character costs a whole byte. That length is the price of a code that any machine can read, and it is why compressed formats exist for storage even though plain binary remains the clearest way to teach the idea.
Common Mistakes With Letter-to-Binary Charts
Five mistakes recur in letter-to-binary work. The first is dropping the leading zero and then counting bits wrong, turning 8-bit A (01000001) into 7-bit A (1000001) mid-message and misaligning everything after it. The second is mixing cases: using the uppercase code for a lowercase letter, or vice versa, which changes the decoded text even though the letters look similar. The third is forgetting the space character, which runs words together on decoding — Hi without its space logic still decodes, but a sentence without spaces decodes as one long word. The fourth is treating binary digits as decimal numbers, so 01000001 gets read as one million one rather than as bits. The fifth is assuming every language fits ASCII: accented letters like e with an acute accent, and scripts like Arabic or Chinese, need Unicode codes that are longer than one byte, and forcing them into an ASCII chart produces either errors or mojibake. The defense is simple: use 8 bits per letter, keep case straight, include the space code, and reach for a full text to binary converter whenever the text goes beyond plain English letters.
Quick Answers
What is A in binary? 01000001 (8-bit) or 1000001 (7-bit). What is a in binary? 01100001. What is Z in binary? 01011010, and z is 01111010. What is the difference between uppercase and lowercase binary? Exactly 32 in decimal, or one flipped bit. What is a space in binary? 00100000. How do you convert a letter to binary by hand? Take its decimal value (uppercase = 64 + position, lowercase = 96 + position) and write it in powers of two. For related guides, read our binary to ASCII by hand guide, our text to binary by hand guide, and our binary to hexadecimal guide. For any text, use the free text to binary converter.