ASCII Table - ASCII Encoding

This ASCII table query tool is a practical reference for developers and learners. Below is a detailed usage guide:

Basic Lookup: When the page opens, it displays a complete table of all 128 standard ASCII characters by default. The table shows, from left to right, the decimal value, hexadecimal value, octal value, binary value, character display, HTML entity encoding, and character description. You can browse directly to find the character information you need.

Category Filtering: Click the filter tags above the table (All, Control Characters, Printable Characters, Digits, Uppercase Letters, Lowercase Letters, Punctuation) to quickly filter specific categories of characters. For example, selecting the "Digits" tag will show only the complete information for characters 0-9 (ASCII values 48-57).

Search Function: Enter keywords in the search box to search by decimal value (e.g. "65"), hexadecimal value (e.g. "41"), the character itself (e.g. "A"), or description text (e.g. "newline", "LF"). Search results update in real time, making it easy to quickly locate the target character.

One-Click Copy: Click any value in the table (such as decimal or hexadecimal) to copy the corresponding value to the clipboard. A "Copied" notification appears at the top of the page, allowing you to use the value directly in your code.

ASCII tables have a wide range of applications in programming and system development. Here are a few typical examples:

Serial Port Communication Debugging: In embedded development and IoT projects, serial port communication is the primary method of data exchange between devices. Developers often need to send specific control characters (such as SOH, STX, ETX) to mark the start and end of data frames. This tool helps developers quickly look up the decimal or hexadecimal values of these control characters to ensure correct implementation of communication protocols.

Text File Format Conversion: Different operating systems use different line endings: Windows uses CRLF (ASCII 13+10), Unix/Linux uses LF (ASCII 10), and older Mac systems use CR (ASCII 13). During cross-platform development or file processing, developers need to understand these differences. This tool visually displays the values and meanings of these control characters, helping troubleshoot line-ending-related issues.

HTML Entity Encoding: In web development, certain special characters (such as <, >, &, etc.) must be escaped as HTML entities to display correctly on a webpage. This tool provides the corresponding HTML entity encoding for each ASCII character, making it easy for developers to quickly look up and use them.

About ASCII Table

The ASCII table (American Standard Code for Information Interchange) is one of the most important character encoding standards in computer history. It defines an encoding scheme for 128 characters, covering English letters, digits, punctuation marks, and control characters. ASCII encoding uses 7 binary digits to represent each character, numbered from 0 to 127. Among these, 0-31 and 127 are control characters, while 32-126 are printable characters. The ASCII table query tool displays these characters' decimal, hexadecimal, octal, and binary representations together, making it easy for developers to look them up at any time.

How to Use the ASCII Table Query Tool

Using this tool is very simple. First, you can enter a decimal value (e.g. 65), hexadecimal value (e.g. 41), the character itself (e.g. A), or description text (e.g. newline) in the search box to quickly locate the target character. Second, click the filter tags above to view characters by category: control characters, printable characters, digits, uppercase letters, lowercase letters, or punctuation. Finally, click any value in the table to copy that encoding with one click, making it convenient to use directly in programming or serial port debugging. The entire query process responds in real time without refreshing the page.

Related Knowledge of ASCII Table & ASCII Encoding

ASCII encoding was first published in 1963 and updated in 1967. Its design took into account the keyboard layout of the prevalent teletype machines of the time. Standard ASCII uses 7-bit encoding, with 128 characters in total. Later, people used the extra 128 positions (128-255) in an 8-bit byte to define extended ASCII character sets, such as ISO-8859-1 and Windows-1252. Before Unicode emerged, ASCII was the universal standard for computer communication in the English-speaking world. ASCII and Unicode are closely related: the first 128 characters of Unicode correspond exactly to ASCII, so any text compatible with ASCII has identical byte representation under UTF-8 encoding. Understanding the ASCII table helps troubleshoot common issues such as garbled text and line-ending differences (such as CRLF vs. LF).