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Output Format
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Binary Output
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Character Breakdown
ASCII value table for each input character
Char Dec Bin Hex Oct
Bit Pattern Visualizer (first 16 chars)

Common ASCII Character Quick Reference

Frequently used ASCII characters and their binary, hex, octal, and decimal equivalents:

Char Decimal Binary Hex Octal
Space320010000020040
A650100000141101
a970110000161141
Z90010110105A132
z122011110107A172
0480011000030060
9570011100139071
!330010000121041
@640100000040100
NUL00000000000000
LF10000010100A012
CR13000011010D015
DEL127011111117F177

ASCII & Binary Encoding — Complete Guide

What Is ASCII?

ASCII (American Standard Code for Information Interchange) is a character encoding standard first published in 1963 by the American National Standards Institute (ANSI). It uses 7 bits to represent exactly 128 characters: 33 non-printable control characters (codes 0–31 and 127) and 95 printable characters (codes 32–126) including uppercase and lowercase letters, digits 0–9, punctuation marks, and the space character.

How Binary Representation Works

Every ASCII character is assigned a decimal number (0–127). To convert that number to binary, you express it in base-2 notation using only 0s and 1s. Computers store characters in 8-bit bytes, so ASCII values are left-padded with a leading zero to fill 8 bits. For example: 'H' has decimal value 72, which equals 01001000 in 8-bit binary.

Hexadecimal and Octal Uses

Hexadecimal (base-16) provides a compact way to represent binary data, since one hex digit maps to exactly 4 binary bits (a nibble), and one byte is always two hex digits. This makes hex invaluable in memory addresses, color codes (#FF5733), and bytecode. Octal (base-8) was historically used in Unix file permissions — for example, chmod 755 sets owner read/write/execute (7 = 111₂), group read/execute (5 = 101₂), and others read/execute (5 = 101₂).

Extended ASCII, Unicode & UTF-8

Standard ASCII only covers English characters. Extended ASCII uses all 8 bits to add 128 more characters (codes 128–255), including accented letters. For international text, Unicode provides over 1.1 million code points covering every language, emoji, and symbol. UTF-8 encodes Unicode using 1–4 bytes per character and is backward-compatible with ASCII for the first 128 values, making it the dominant encoding on the web today.

Converting Text to Binary — Step by Step

  • Find each character's ASCII decimal code (e.g., 'H' = 72).
  • Divide the decimal value by 2 repeatedly, recording remainders.
  • Read remainders bottom-to-top to get the binary number (72 → 1001000).
  • Pad to 8 bits with leading zeros (01001000).
  • Repeat for every character and separate groups as needed.

Why This Converter Is Useful

Developers use ASCII-to-binary conversion when debugging serial communications, analyzing raw file formats, studying network protocols, and working with embedded systems. Students use it to understand how computers store text. Security researchers use hex and binary representations to analyze encoded payloads and binary files.

Frequently Asked Questions About ASCII & Binary Conversion

To convert ASCII text to binary, find the decimal value of each character using the ASCII table, then convert each decimal to its 8-bit binary form. For example, 'A' = decimal 65 = binary 01000001. For the word "Hi": H = 01001000, i = 01101001. Use the converter above to do this instantly for any text.
The binary code for "Hello" is: 01001000 01100101 01101100 01101100 01101111 — H=01001000 (72), e=01100101 (101), l=01101100 (108), l=01101100 (108), o=01101111 (111).
Standard ASCII characters are defined with 7 bits, covering values 0–127. However, computers store them in 8-bit bytes (octets), with the most significant bit set to 0 for standard ASCII. Extended ASCII uses all 8 bits to represent values 0–255. This converter defaults to 8-bit display, but you can switch to 4, 16, or 32 bits using the Bit Width options.
ASCII is a character encoding system — it maps characters to numbers (e.g., 'A' = 65). Binary is a number system — a base-2 way of representing any integer using only 0s and 1s. "ASCII to binary" means taking each character's ASCII decimal code and expressing it in binary form. Binary itself is not a text format; it's how computers represent all numbers internally.
The space character has ASCII decimal code 32. In binary it is 00100000, in hexadecimal it is 20, and in octal it is 040. Space is the first printable ASCII character (code 32), and all codes below 32 are non-printable control characters.
To convert binary to text: (1) Split the binary string into 8-bit groups. (2) Convert each 8-bit group to its decimal value. (3) Look up the ASCII character for that decimal code. For example, 01001000 = 64+8 = 72 = 'H'. Use the "Binary → Text" tab in this tool to reverse-convert instantly. The converter accepts space-separated, comma-separated, or continuous binary strings.
The 0b prefix is a common programming convention indicating that the number following it is in binary (base-2). For example, 0b01000001 means the binary number 01000001, which equals 65 in decimal (ASCII 'A'). Similarly, 0x denotes hexadecimal and 0o denotes octal. Toggle the "Add prefix" option in this converter to include these prefixes in your output.
Yes, this tool is completely free with no registration required. All conversion happens directly in your browser (100% client-side JavaScript) — no data is sent to any server. There is no usage limit, and you can convert any amount of text, download results as a .txt file, and use all features including the ASCII reference table, bit visualizer, and conversion history.