ASCII Table reference

Complete 7-bit ASCII character set. Search by decimal, hex, octal, binary, or character name. Filter by control characters or printable glyphs. Click to copy any character.

All (0–127)
Control Characters (0–31, 127)
Printable (32–126)
128 characters Click to copy character Standard ASCII (ISO/IEC 646)
DecHexOctBinCharDescription / NameCopy
Loading ASCII data...
Privacy first: All data processed locally. No keystrokes or searches are sent to any server.

The ASCII Standard: Foundation of Modern Computing

ASCII (American Standard Code for Information Interchange) is a character encoding standard for electronic communication, developed from telegraph codes and first published in 1963. It uses 7 bits to represent 128 unique characters: 33 non-printing control characters (many now obsolete) and 95 printable characters including digits, uppercase/lowercase Latin letters, punctuation, and space.

Decimal 65 → Hex 41 → Binary 1000001 → Character 'A'
Decimal 97 → Hex 61 → Binary 1100001 → Character 'a'
Decimal 10 → Hex 0A → Line Feed (LF)

ASCII codes are the basis of nearly all text files, network protocols, and programming languages.

Why ASCII Still Matters in the UTF-8 Era

Although Unicode has largely replaced ASCII for international text, ASCII remains the foundational subset of UTF-8 (every valid ASCII byte sequence is also valid UTF-8). All modern operating systems, programming languages (C, Python, JavaScript), and protocols (HTTP, SMTP, JSON) rely on ASCII for keywords, operators, and structural syntax. Understanding ASCII codes is essential for debugging binary data, designing network packets, parsing low-level file formats, and even reverse engineering.

The control characters (0–31 and 127) were originally designed for teletype machines: Carriage Return (CR, 13) and Line Feed (LF, 10) still define line endings across platforms, while Null (NUL, 0) terminates strings in C. The printable range includes digits, letters, and punctuation that form the core of English-alphabet computing.

ASCII Table Structure

The table is divided into three logical groups:

  • Control characters (0–31, 127): Non-printing commands (e.g., NUL, SOH, STX, ETX, EOT, ENQ, ACK, BEL, BS, HT, LF, VT, FF, CR, SO, SI, DLE, DC1–DC4, NAK, SYN, ETB, CAN, EM, SUB, ESC, FS, GS, RS, US, DEL). Many are historical relics, but LF, CR, TAB, ESC, and DEL remain actively used.
  • Printable characters (32–126): Space (32), digits 0–9 (48–57), uppercase A–Z (65–90), lowercase a–z (97–122), and punctuation/symbols.
  • Delete (127): Often considered a control character, originally used to punch out erroneous characters on paper tape.
Case Study: ASCII in Network Protocols

The HTTP protocol (the foundation of the World Wide Web) uses ASCII text for request methods (GET, POST), headers (Host:, User-Agent:), and status codes (200 OK, 404 Not Found). SMTP (email) likewise uses ASCII commands (HELO, MAIL FROM, RCPT TO). By mastering the ASCII table, developers can read raw network traffic, craft custom HTTP requests, and debug text-based protocols without specialized tools. Our interactive table helps you quickly look up the exact code for carriage return (13) or line feed (10) when constructing TCP packets.

How to Use This ASCII Reference

  1. Browse the full table or filter by "Control characters" or "Printable".
  2. Use the search box to find a character by decimal (e.g., "65"), hexadecimal (e.g., "0x41"), binary, or name (e.g., "newline", "tab").
  3. Click the copy button next to any character to copy it to your clipboard – useful for inserting special characters like DEL or ESC into code or documents.
  4. Use the decimal, hex, octal, and binary columns for programming reference (e.g., in C/C++ escape sequences: '\n' = LF, '\r' = CR, '\t' = TAB).

ASCII Extensions & Limitations

Standard ASCII is limited to English letters and a few symbols. For accented characters (é, ñ, ü) or non-Latin scripts, extended ASCII (ISO-8859-1, Windows-1252) or Unicode (UTF-8) must be used. However, all those encodings retain the original 128 ASCII codes as their first 128 code points, ensuring backward compatibility. This is why ASCII remains universally relevant.

Common ASCII Escape Sequences (Programming)

'\0' (NUL), '\n' (LF, 10), '\r' (CR, 13), '\t' (TAB, 9), '\b' (BS, 8), '\e' (ESC, 27), '\\' (Backslash, 92), '\'' (Single quote, 39), '\"' (Double quote, 34)

Frequently Asked Questions

ASCII uses 7 bits (128 characters) and covers only English letters, digits, and basic symbols. Unicode supports over 149,000 characters from virtually all writing systems. UTF-8, the most common Unicode encoding, is backward-compatible with ASCII: any valid ASCII text is also valid UTF-8.

These originate from early communication protocols (start of heading, start of text, end of text) used in teleprinters and mainframe networks. While largely obsolete, they occasionally appear in legacy data streams or custom binary protocols.

On Windows, hold Alt and type the decimal code on the numeric keypad (e.g., Alt+65 for 'A'). On macOS, use Option + hexadecimal (needs Unicode Hex Input). Linux: Ctrl+Shift+U then hex code.

CR (Carriage Return, 13) moves the cursor to the beginning of the line. LF (Line Feed, 10) moves the cursor down one line. Windows uses CR+LF for line breaks, Linux/macOS use LF only.

Yes, this tool includes every character from 0 to 127 inclusive, with correct decimal, hexadecimal, octal, binary, and standard names as defined by the ANSI X3.4-1986 standard.

Trusted reference: ASCII definitions follow the original ANSI X3.4-1986 (R1997) and ISO/IEC 646:1991 standards. Data validated against authoritative sources including the Unicode Consortium and IANA character set registrations. Reviewed by computer science educators and systems programmers. Last update: May 2026.

References: IANA Character Sets, Wikipedia: ASCII, Unicode Consortium, "The ASCII Standard" – ANSI X3.4-1986.