Binary Translator

How text becomes binary

Computers store text as numbers. This translator uses UTF-8, the encoding used by almost all web pages: every character is turned into one to four bytes, and each byte is written as eight bits (binary digits). A bit is 0 or 1, and the eight positions are worth 128, 64, 32, 16, 8, 4, 2 and 1. Adding the positions that hold a 1 gives the byte value — 01000001 is 64 + 1 = 65, the letter A.

Decoding works in reverse: the binary is split into groups of eight, each group becomes a byte, and the bytes are read as UTF-8 text.

How to convert text to binary step by step

Here is the word Cat converted by hand.

1. Find each character's code. In ASCII (and UTF-8, which matches ASCII for these characters) C is 67, a is 97 and t is 116. Upper and lower case have different codes.
2. Write each number as a sum of powers of two. The eight bit positions are worth 128, 64, 32, 16, 8, 4, 2 and 1. 67 = 64 + 2 + 1. 97 = 64 + 32 + 1. 116 = 64 + 32 + 16 + 4.
3. Put a 1 in each used position and 0 elsewhere. 67 becomes 01000011, 97 becomes 01100001 and 116 becomes 01110100. Always keep eight digits, adding leading zeros.
4. Join the bytes. Cat = 01000011 01100001 01110100. The same bytes are 43 61 74 in hexadecimal, 67 97 116 in decimal and 103 141 164 in octal.

To decode binary to text, do the same in reverse: split the digits into groups of eight, add up the position values of each 1 to get a number, and look the number up in the table below.

Hex, decimal and octal output

Binary, hexadecimal, decimal and octal are just different ways of writing the same byte values. Hexadecimal (base 16) uses two digits per byte, 00 to FF, and is common in programming and network tools. Decimal shows each byte as a number from 0 to 255. Octal (base 8) uses three digits per byte, 000 to 377. Pick the format with the Output format menu, and the separator menu to put a space, a comma or nothing between bytes.

Examples to try

• A → 01000001 (65).
• Hi → 01001000 01101001. Paste that back and choose Binary → Text to get Hi again.
• é → 11000011 10101001. Accented letters need two bytes in UTF-8.
• A space character is 00100000 (32), so "Hi there" contains one more byte than its letters.

Common mistakes

• Dropping leading zeros. A is 01000001, not 1000001. Without the leading zero the total length is no longer a multiple of 8 and the bytes shift.
• Mixing in other characters. Only 0, 1, spaces, line breaks and commas are accepted when decoding. Letters such as O or l typed instead of 0 or 1 cause an error.
• Assuming one byte per character. Emoji and many non-English letters take two to four bytes. Cutting the binary in the middle of such a character makes the bytes invalid UTF-8.
• Confusing case. Uppercase and lowercase letters differ by 32, which is a single bit: A is 01000001 and a is 01100001.

Binary table for common characters

What is ASCII?

ASCII is the original 7-bit character code for English text: 128 codes for letters, digits, punctuation and control characters. Printable characters are codes 32 to 126. UTF-8, which this translator uses, encodes these characters with the same single byte, so for plain English text ASCII and UTF-8 binary are identical. Letters outside ASCII, such as é or emoji, take two to four bytes in UTF-8.

Binary to text (decoding)

1. Split the binary into groups of 8 bits (one byte each).
2. Convert each byte to a number: 01001000 = 72 and 01101001 = 105.
3. Look the numbers up in the ASCII table above (or decode as UTF-8 for other characters): 72 is H and 105 is i.

So 01001000 01101001 decodes to Hi. Paste binary into the translator above and it does this for you, and tells you if the length is not a multiple of 8 bits or the bytes are not valid text.

Frequently asked questions