ASCII to Binary Converter

An ASCII-to-binary converter takes each character of your input, looks up its seven-bit code point, pads it to a full byte and prints the eight bits in zeros and ones. Useful for computer-science homework, for reading a hex dump byte by byte, and for writing test fixtures for low-level serial or network code where you need to see exactly which bits cross the wire.

How ASCII becomes binary

  1. 1

    Paste your text

    Any printable ASCII character is accepted. Letters, digits, punctuation, space.

  2. 2

    Each character is mapped to a decimal code

    For example, `A` is 65, `a` is 97, space is 32.

  3. 3

    That decimal becomes 8-bit binary

    65 in binary is `01000001`. The leading zero pads it to a full byte.

  4. 4

    Bytes are joined with spaces

    So `Hi` becomes `01001000 01101001`. Change the separator if your target format expects something else.

Worked example

The word Cat encodes as:

Char Decimal Binary
C 67 01000011
a 97 01100001
t 116 01110100

Concatenated: 01000011 01100001 01110100.

Why 8 bits and not 7?

ASCII is defined as a 7-bit code — values 0-127. But every modern machine stores characters in whole bytes, so the top bit is always present and is always zero for pure ASCII. Padding to 8 bits matches what you will see in a hex editor or a Wireshark trace.

Non-ASCII input

Characters above U+007F (accented letters, emoji, CJK) are not ASCII. If the input is UTF-8 encoded, one character may take 2, 3 or 4 bytes. For example, \u00e9 (e-acute) is 11000011 10101001 in UTF-8 — a two-byte sequence. This converter treats each UTF-8 byte as a unit.

Common use cases

  • Education — Computer Science 101, showing how text becomes bits.
  • Protocol debugging — Knowing that GET at the start of an HTTP request is 01000111 01000101 01010100 00100000.
  • Obfuscation puzzles — Binary text is a common genre of escape-room puzzle and CTF challenge.

Frequently Asked Questions

Because ASCII only goes up to 127, so the most significant bit of every ASCII byte is zero. Strings that include non-ASCII UTF-8 bytes will have leading ones on the continuation bytes.

Yes — use the Binary to ASCII Converter. It accepts any 8-bit grouping with or without separators.

Yes. Each newline is a single byte (LF = 0x0A = 00001010) or two bytes (CRLF = 0x0D 0x0A) depending on where you copied from. The converter passes them through as ordinary characters.

Space between bytes is the most readable. Use no separator if you are pasting into a fixed-width parser. Some CS courses expect hyphens or dots — pick whichever matches the rubric.

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