ASCII Character Converter

ASCII Converter

ASCII Converter — Text to ASCII Codes and Back

ASCII (American Standard Code for Information Interchange) is the foundational character encoding standard used in computers, networking, and programming. This free converter translates any text into its ASCII codes in decimal, hexadecimal, and binary formats, and converts any code number back to its character. Supports the full range from 0 to 255.

What Is ASCII?

ASCII was developed in the 1960s for use in teletype machines and early computers. The original standard defines 128 characters (0–127): 33 non-printable control characters (like newline, tab, backspace), 94 printable characters (letters, digits, punctuation), and a space. Extended ASCII (128–255) includes additional characters for accented letters, box-drawing characters, and symbols, with variations depending on the code page.

Key ASCII Ranges

  • 0–31: Control characters (NUL, SOH, LF=10, CR=13, TAB=9, etc.)
  • 32: Space character
  • 48–57: Digits 0–9
  • 65–90: Uppercase letters A–Z
  • 97–122: Lowercase letters a–z
  • 33–47, 58–64, 91–96, 123–126: Punctuation and symbols
  • 127: DEL (delete)
  • 128–255: Extended ASCII (code page dependent)

Why Is ASCII Important in Programming?

Many programming tasks rely on ASCII values: comparing characters arithmetically (e.g., 'Z' - 'A' = 25), converting between uppercase and lowercase (add or subtract 32), validating input (check if code is in the digit or letter range), parsing text files, implementing encryption, and building simple data structures. In C and many other languages, characters are simply small integers equal to their ASCII values.

ASCII vs. Unicode

Modern software uses Unicode (UTF-8, UTF-16) which covers over 140,000 characters across all human writing systems. However, the first 128 Unicode code points are identical to ASCII, so ASCII remains fully valid and is still the dominant encoding for English text, source code, configuration files, and internet protocols.

Frequently Asked Questions

What is the ASCII code for Enter/newline?
Line Feed (LF) is ASCII 10 (0x0A). Carriage Return (CR) is ASCII 13 (0x0D). On Unix/Linux systems, a newline is just LF. On Windows, a newline is CR+LF. On older Mac systems (before OS X), it was CR alone.
Why do uppercase and lowercase letters differ by 32?
This was a deliberate design choice. Bit 5 (value 32) acts as a case flag: 0 for uppercase, 1 for lowercase. This means a single bit flip converts between cases, making case conversion extremely efficient in hardware and software.
What is the difference between ASCII and UTF-8?
UTF-8 is a variable-width encoding for all Unicode characters. For the first 128 characters, UTF-8 uses the same single byte as ASCII — so any valid ASCII document is also valid UTF-8. For characters 128 and above, UTF-8 uses two to four bytes, while ASCII only defines single bytes for 128–255 through extended code pages.
What are control characters used for?
Control characters were designed for teletype communication control: SOH (start of header), STX (start of text), ETX (end of text), EOT (end of transmission), ENQ (enquiry), ACK (acknowledge), BEL (ring bell), BS (backspace), HT (horizontal tab), LF (line feed), and CR (carriage return) are the most commonly encountered today.
Can I convert emoji or other Unicode characters here?
This tool works with ASCII and extended ASCII (0–255). Emoji and other Unicode characters have code points above 255 and require Unicode-aware tools. For emoji and multilingual text, use a full Unicode code point converter.