Binary Translator

How a letter becomes eight ones and zeros

A computer has no concept of the letter H. What it stores is a number, and what it displays depends on which table it looks that number up in. The letter H has been assigned the number 72 since the early days of ASCII, and every modern system still agrees on that. Write 72 in base 2 and you get 1001000. Pad it to a full byte and you get 01001000.

That is the whole trick. Every conversion on this page is the same two steps: turn the text into a list of byte values, then print each value in the base you chose.

Worked example: the word "Hi"

Put Hi in the left box with Binary selected and you get:

01001000 01101001

The first group is H (72). The second is lowercase i, which is 105, or 01101001. Switch the base row to Hexadecimal without changing the text and the same two bytes print as 48 69. Switch to Decimal and they print as 72 105. Nothing about the data changed; only the notation did.

Hex is the one professionals reach for, because two hex digits cover exactly one byte with no padding and no ambiguity. Binary is the one that makes the idea visible. Decimal is the one that matches what you see in most programming language character tables.

Where ASCII stops and UTF-8 begins

ASCII only ever defined values 0 to 127. That covers unaccented English letters, digits, common punctuation and a set of control codes. Everything else, which is to say most of human writing, sits above 127 and needs a broader scheme.

This tool encodes text as UTF-8 before converting, which is what browsers, web servers and virtually every modern file format do. UTF-8 keeps the original 128 ASCII values as single bytes, so plain English text produces exactly one group per character. Anything beyond that expands: most accented Latin letters and Greek and Cyrillic take two bytes, most CJK characters take three, and emoji take four.

So é is not one group, it is 11000011 10101001 (hex C3 A9). A single emoji typically prints as four groups, and an emoji built from a joined sequence, like a family or a flag, can print as a dozen or more. That is not a bug in the converter. It is genuinely how the character is stored on disk.

What the decoder expects you to paste

Switch to "Code → Text" and the parser splits your input on any run of whitespace, then reads each token in the selected base. Every token has to land between 0 and 255, because every token represents one byte. If a token cannot be parsed, or comes out above 255, the status line names the offending token instead of silently producing garbage.

Practical consequences worth knowing:

• Binary groups do not have to be padded to eight digits. 1001000 parses the same as 01001000.
• Hex is read two digits per byte. A continuous blob like 48656c6c6f with no spaces will be read as one enormous number and rejected. Space it out.
• Decimal tokens above 255 fail for the same reason. There is no such thing as byte 4096.
• Commas are not separators here. Strip them before pasting.

Who actually uses this

Students sitting computer science units get set the exercise of hand-converting their name to binary, and checking the answer here is faster than checking it against a printed ASCII chart. Developers chasing an encoding bug use it to see whether a file really contains the bytes they expect, or whether a mojibake string is UTF-8 that got read as Latin-1. Puzzle and escape room builders use binary as a low-effort layer of obfuscation, usually printed on a prop.

If the goal is a clue rather than a lesson, the letter substitutions on the Cipher Decoder page reward solving, and Morse Code can be tapped or flashed instead of printed. If you need to move real binary data through a text channel rather than just look at it, Base64 Encode & Decode is the right format, because it is far more compact than eight characters per byte.

Common questions

Why does one emoji produce four groups instead of one?

UTF-8 uses a variable number of bytes per character. Emoji sit high in the Unicode range and need four bytes each, so they print as four groups. Some emoji are actually several characters joined together and will produce even more.

Can I paste binary with no spaces between the bytes?

No. The decoder splits on whitespace and reads each token as one byte value, so an unbroken run of ones and zeros is treated as a single number and rejected. Insert a space every eight digits.

Is binary here the same as the binary in a file's raw contents?

For text, yes: these are the exact bytes a UTF-8 file would contain. Binary files like images or executables are not text at all, so pasting their contents into the text box will not give you a meaningful result.

Why is hex preferred over binary in real work?

Compactness with no loss of precision. Two hex digits map to exactly one byte and to exactly eight binary digits, so hex is four times shorter to read and write while still letting you see individual bit groups at a glance.

Does my text get sent anywhere?

No. Conversion uses the browser's built-in TextEncoder and TextDecoder, so your text stays in the tab and nothing is transmitted.