Binary and Hex Text Converter

What this tool does

Every piece of text a computer handles is ultimately a sequence of bytes — numbers from 0 to 255. This converter shows you that sequence, in whichever base you choose, and converts it back. Binary shows each byte as eight bits, hex as two hexadecimal digits, octal as three octal digits, and the decimal view as the plain byte values separated by spaces.

The reason to prefer this over an ASCII-only converter is UTF-8. English letters map to one byte, but an accented letter, a Greek or Cyrillic letter, a Chinese character or an emoji takes two to four bytes, and the tool handles that splitting and joining for you. Typical uses are checking what a protocol or file format actually contains, debugging a mojibake problem where text was decoded with the wrong charset, teaching how character encoding works, and decoding a byte dump pasted out of a log or a hex editor.

Method

Encoding runs the input through the browser's UTF-8 encoder, which yields a byte array, then formats each byte according to the selected base — toString(2) padded to eight bits, toString(16) padded to two digits, toString(8) padded to three, or the raw decimal value. Decoding reverses this: binary input is split into eight-bit groups when the digit count divides evenly by eight, hex is read in pairs, and octal and decimal are read as separate numbers; the resulting bytes are handed to the UTF-8 decoder.

Text	Binary	Hex	Decimal
A	01000001	41	65
a	01100001	61	97
space	00100000	20	32
é	11000011 10101001	C3 A9	195 169

Example

Text	Hex (UTF-8)
Hi	48 69
Hello	48 65 6C 6C 6F
café	63 61 66 C3 A9

Binary, octal, decimal and hex are the same number

The base a number is written in does not change the value — 255, 0b11111111, 0377 and 0xFF are the same integer in four notations. Which one you use is a question of what reads best in the context: binary shows the individual bits, hex groups four bits per digit, and octal groups three.

Base	Digits	One digit is	Readable for
2	0–1	1 bit	Flags, bitmasks, protocol fields
8	0–7	3 bits	Unix file modes, legacy systems
10	0–9	—	Values a person reads
16	0–9 A–F	4 bits	Bytes, colours, hashes, memory dumps

Hex is the practical default for bytes because two hex digits are exactly one byte — which is why a memory address or a colour is written as pairs. Binary is clearer when you need to see individual flags; octal survives mainly because file permissions (0755) are conventionally written that way.

Text to binary is not converting a number

There are two different operations that both get called “text to binary”. One encodes each character as its code point in binary — A is 65, so 1000001. The other encodes the UTF-8 bytes of the string, which for ASCII is the same thing and for anything else is not: a character such as é becomes two bytes, so two eight-bit groups. This tool states which representation it produces, because decoding the wrong one gives a plausible but wrong string.

Bits, bytes and word size

A byte is eight bits. A “word” is architecture-dependent — 32 or 64 bits on modern hardware — and that matters when reading a binary dump: the same bytes interpreted as big-endian or little-endian 32-bit words give different numbers. A converter that works on bytes sidesteps the question; one that claims to show “the value” has to state its byte order.

Frequently asked questions

Go deeper

Longer explanations of the problems this tool solves:

Bytes, hex and entities: the same text in four notations

Sources

• Unicode Standard and RFC 3629, UTF-8, a transformation format of ISO 10646.
• WHATWG Encoding Standard, for the byte-level behaviour of the browser's UTF-8 encoder and decoder.