Binary to Text Converter
Eight bits to a byte. Non-ASCII characters take more than one.
Letters are numbers, and numbers are bits
Computers store text as numbers. The letter A is 65, B is 66, and so on — the ASCII assignment from 1963. Written in binary, 65 is 01000001.
Eight bits make a byte, which can hold 256 values. That was enough for English, some punctuation and a few control codes, and not enough for anything else.
Why some characters take more bytes
Modern text is UTF-8, which is variable length:
- 1 byte for anything in the original ASCII range, which is why UTF-8 is backwards compatible with it.
- 2 bytes for most accented Latin letters, Greek and Cyrillic.
- 3 bytes for most Chinese, Japanese and Korean characters.
- 4 bytes for emoji and rarer scripts.
So "café" is five bytes, not four. Type an emoji above and watch the byte count jump — that is the same effect that makes a tweet with emoji count differently from one without.
The tidy trick in how UTF-8 works
A byte starting with 0 is a single character. A byte starting with 110 begins a two-byte sequence, 1110 a three-byte one, and every continuation byte starts 10.
That means you can drop into the middle of a UTF-8 stream and find the next character boundary by looking for a byte that does not start 10. It is self-synchronising, which is a genuinely elegant piece of design and the reason UTF-8 won.
Reading binary by eye
Each position doubles: 128, 64, 32, 16, 8, 4, 2, 1. Add up the positions holding a 1. 01000001 is 64 + 1 = 65 = A.
Two shortcuts worth knowing: uppercase letters run from 65, lowercase from 97, and the difference is exactly 32 — a single bit. Flipping bit six changes case. Digits start at 48, so the low four bits of a digit byte are the digit itself.
Common uses
- Puzzles and CTF challenges.
- Teaching how text is stored.
- Checking an encoding problem by looking at actual bytes.
- Decoding something found in a file or a message.
Questions people ask
How is text stored as binary?
Each character maps to a number, and the number is written in base 2. A is 65, which is 01000001.
Why does my text produce more bytes than characters?
Because UTF-8 is variable length. Accented letters take two bytes, most CJK characters three, and emoji four.
How many bits in a byte?
Eight, giving 256 possible values. That is why binary text comes in groups of eight.
How do I read binary by eye?
Each position doubles: 128, 64, 32, 16, 8, 4, 2, 1. Add the positions holding a 1.
What is the difference between uppercase and lowercase in binary?
Exactly one bit. Uppercase starts at 65 and lowercase at 97, a difference of 32.
None of this is security
The ciphers on this site are historical. Every one of them was broken centuries ago, and a modern computer breaks them in microseconds — the Caesar page shows the break happening rather than just describing it.
They are worth knowing for puzzles, for teaching, for reading old texts and for understanding where cryptography came from. They are not worth using to protect anything. If you need something kept secret, you need modern encryption with a properly managed key, and you should not be building it yourself.
The encodings — Morse, binary, hex, NATO — make no secrecy claim at all. They exist to move information over a channel, and anyone can read them.
Your text stays in the page
Everything runs in your browser. Nothing you type is transmitted, logged or stored, and this site has no server that could receive it. The about page lists every request the site makes.