How to convert text to binary (and back)
- Paste your text, or a string of 0s and 1s, into the top box.
- Choose Text → Binary to encode or Binary → Text to decode. When encoding, untick Group bytes with spaces if you need one unbroken string instead of 8-bit chunks.
- The result updates a moment after you stop typing. Click Copy result to grab it.
What binary actually is
Computers store everything as bits, switches that are either 0 or 1. Eight bits make one byte, which can hold 256 different values. A letter is stored as a number, and that number is stored as a byte. This tool shows the hidden step: it finds the bytes behind each character and prints them in 8-bit binary.
Worked example: “Hi”
The letter H has the number 72, which is 01001000 in binary. The letter i is 105, or 01101001. So Hi becomes 01001000 01101001, and pasting that back in Binary → Text returns Hi. Upper and lower case differ by a single bit: A is 01000001 and a is 01100001, because the bit worth 32 is switched on for lowercase. Even a line break is a character: it is the byte 00001010.
How UTF-8 changes the byte count
The tool encodes text as UTF-8, so one character can take one to four bytes. The leading bits of each byte tell a decoder how to read it: a byte starting with 0 is a complete character, 110, 1110 and 11110 start a 2-, 3- or 4-byte character, and 10 marks a continuation byte.
- Plain English letters, digits and punctuation: 1 byte, always starting with 0.
- é (U+00E9): 2 bytes,
11000011 10101001. - € (U+20AC): 3 bytes,
11100010 10000010 10101100. - Korean 가 (U+AC00): 3 bytes,
11101010 10110000 10000000. - Emoji such as 😀 (U+1F600): 4 bytes,
11110000 10011111 10011000 10000000.
This is why the same number of visible characters can produce very different amounts of binary. Many textbook examples use 7-bit ASCII; this tool always outputs full 8-bit bytes, so ASCII characters simply start with an extra 0.
Why decoding fails, and what the errors mean
- “Binary can only contain 0s and 1s”: something else is in the input, such as commas, a
0bprefix or hexadecimal digits. Whitespace is the only thing ignored. - “Binary length must be a multiple of 8 bits”: a digit was lost or added, or the source used 7-bit groups. Pad each 7-bit group with a leading 0 and try again.
- Strange � symbols in the output: the bytes were valid binary but not valid UTF-8, for example data from another encoding. The decoder substitutes the replacement character rather than stopping.
Who uses it
Students use it to check computer-science homework on character encoding. Developers use it to inspect the raw bytes of a character that displays wrongly. Teachers and puzzle makers use it to build “decode the message” exercises. Keep in mind that binary is only a different notation for the same text, not encryption: anyone can decode it.
Is it private and safe?
Yes. The conversion runs in your browser, using its built-in text encoder and decoder, on your own device. Your text is never uploaded anywhere.
Related guides
To see the same bytes in another notation, try the Base64 text encoder. For a fixed-length fingerprint of text, use the hash generator, or flip a string around with Reverse Text.
Frequently asked questions
Is this ASCII or UTF-8?
UTF-8. Each character is encoded to its UTF-8 bytes, so English letters take one byte while accented letters, Korean, Japanese and emoji take two to four. Plain ASCII text produces the same bytes under both, with a leading 0 on each.
How do I convert binary back to text?
Switch the mode to Binary to Text and paste the binary. Spaces, tabs and line breaks between bytes are ignored, so grouped and unbroken binary both work. The input must contain only 0s and 1s and its length must be a multiple of 8.
Why does my binary show an error about a multiple of 8?
Every byte is exactly 8 bits, so a valid string has a length divisible by 8. The usual causes are a missing or extra digit, or source data that uses 7-bit ASCII groups. Pad 7-bit groups with a leading 0 to make them 8 bits.
Why do some characters produce more than 8 bits?
UTF-8 uses one byte for basic ASCII but two to four bytes for everything else. A character such as the euro sign is three bytes, so it appears as three 8-bit groups. Emoji use four.
What are the odd symbols I see after decoding?
The replacement character means the bytes were not valid UTF-8, so the decoder could not turn them into a real character. This often happens when binary came from a different encoding or was cut off mid-character.
Does spacing matter when decoding?
No. All whitespace is stripped before decoding, so binary grouped into bytes and binary written as one long run decode to the same text. The Group bytes option only affects encoding output.
Is binary a form of encryption?
No. Binary is just another way of writing the same bytes, and anyone can reverse it, including with this tool. Do not rely on it to hide sensitive information.
Is my text uploaded?
No. Everything runs in your browser on your device and nothing is sent to a server.