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Converting text to binary by hand takes three moves per character: find the character’s code (A = 65, a = 97), convert that decimal number to binary by subtracting powers of two, and pad the result to 8 bits. For “Hi” the whole thing is: H → 72 → 01001000, i → 105 → 01101001. Below is the full 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
- Mistake: dropping the leading zeros.
1001000is the right math but only 7 bits. Correction: pad every byte to 8 bits —01001000— or every following byte shifts and the message decodes as garbage. - Mistake: forgetting the space byte. Correction: a space is a character too — code 32, binary
00100000. “Hi there” has a byte for the space between the words. - Mistake: mixing up uppercase and lowercase. A is 65 but a is 97 — the two forms differ by exactly 32, and “Hi” and “hi” produce different bytes. Correction: check the case before looking up the code.
- Mistake: arithmetic slips in the subtraction. Correction: add the place values back to verify — the 1-positions of
01101001are 64 + 32 + 8 + 1 = 105, which must equal the code you started from.
Skip the arithmetic
The text to binary converter turns any message into clean 8-bit bytes as you type — free, private, and right in your browser.
Open the text to binary converterCheck 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 the text to binary converter handles the other direction instantly.
A Four-Point Self-Check
- Convert “Hi” with the tool and compare byte for byte:
01001000 01101001. - Count bytes against characters — one byte per letter, digit and space.
- Paste your binary back and decode it — it must return your exact original text, case included.
- Pick one byte and re-add its place values by hand; the sum must equal the character’s code.
One honest limit: hand conversion suits short text only. Past a sentence or two, the error rate climbs fast — use the tool for anything longer. And this checklist only covers single-byte English text; multi-byte UTF-8 characters are a different process.
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.
What is “Hi” in binary?
“Hi” in binary is 01001000 01101001 — H is code 72 (01001000) and i is code 105 (01101001), one 8-bit byte per character.
What is the binary code for a space?
A space is character code 32, which is 00100000 in binary. It takes a full byte like any letter, which is why “I love you” in binary includes 00100000 between the words.
How do I convert a digit like 7 to binary text?
The character “7” is ASCII code 55, which is 00110111 — not the number 7 (00000111). Digits as text use their character codes, just like letters do.
Is text to binary the same as decimal to binary?
Not quite. Text to binary goes through a character code first: the letter becomes its ASCII/Unicode number, and that number is written in binary. Decimal to binary converts a plain number directly, with no character table involved.
Can I convert emoji to binary by hand?
In theory, but it is impractical: an emoji has a large code point that UTF-8 splits across 3–4 bytes, and the bit-shuffling by hand is error-prone. For emoji and other multi-byte characters, use the translator and open Explain This Result.