Converting text to binary without a tool takes three moves per character: find its code, convert that decimal number to binary, and pad the result to 8 bits. Here is the whole method with a worked example, the mistakes that trip people up, and a few exercises to lock it in.

Why This Method Works

A computer stores text as one number per character. ASCII/Unicode supply the number (the code point), and the byte that holds it is just that number written in base 2. So “text to binary” is really “character to number, number to base 2, pad to a full byte” — nothing more.

Step 1: Find the Character Code

Every character has a number in ASCII/Unicode. A binary alphabet chart lists them: A is 65, B is 66, lowercase a is 97. For “Hi”: H = 72, i = 105. The reference table on our home page covers every letter and digit.

Step 2: Convert Decimal to Binary

Repeatedly subtract the largest place value that fits (128, 64, 32, 16, 8, 4, 2, 1), writing 1 where it fits and 0 where it does not. For 72: 64 fits, 8 fits — giving 1001000. For 105: 64 + 32 + 8 + 1 → 1101001.

Step 3: Pad to 8 Bits

Text bytes are always 8 bits, so add leading zeros: 72 becomes 01001000 and 105 becomes 01101001. Put them together and “Hi” in binary is:

01001000 01101001

Common Mistakes

  • Dropping the leading zeros — 1001000 is the right math but only 7 bits. A text byte must be padded to 8: 01001000. Without padding, every following byte shifts and the message decodes as garbage.
  • Forgetting the space byte — a space is a character too: code 32, binary 00100000. “Hi there” has a byte for the space between the words.
  • Mixing up uppercase and lowercase — A is 65 but a is 97; the two forms differ by exactly 32. “Hi” and “hi” produce different bytes (01001000 vs 01101000 for the first letter).
  • Arithmetic slips — check yourself by adding the place values back: the 1-positions of 01101001 are 64 + 32 + 8 + 1 = 105, which must equal the code you started from.

Check Your Work

Paste your hand-written result into our binary code translator — if it reads “Hi”, you got it right. The translator’s Error Clinic will even point out which byte is wrong if a bit slipped, and it converts text to binary instantly when you want to go the other direction.

Practice

1. Encode “OK” by hand. O = 79 → 64 + 8 + 4 + 2 + 1 → 01001111; K = 75 → 64 + 8 + 2 + 1 → 01001011. Answer: 01001111 01001011.

2. Encode lowercase “a”. a = 97 → 64 + 32 + 1 → 01100001. Compare with uppercase A (01000001) to see the 32-point gap in action.

What About Letters Beyond English?

Characters like 你 or 👋 have code points far above 255, so they need several bytes in UTF-8 — that process is tedious by hand and best left to the converter. The article what is UTF-8 explains how multi-byte encoding works.

Frequently Asked Questions

Why pad to 8 bits instead of 7?

ASCII values fit in 7 bits, but computers store and move data in 8-bit bytes, so text binary is always written in 8-bit groups. A 7-bit group breaks the alignment of every byte after it.

Do I need to memorize the whole ASCII table?

No — three anchors are enough: A = 65, a = 97, 0 = 48. Every other letter or digit is a simple offset from one of them, and a reference table covers the rest.

What about accented letters like é?

é is U+00E9, above the 0–127 range of a single ASCII byte, so UTF-8 stores it as two bytes (11000011 10101001). Multi-byte characters are practical to convert with the translator, not by hand.