ASCII Values Alphabets ( AZ, az & Special Character Table ) (original) (raw)

Last Updated : 13 Dec, 2025

ASCII (American Standard Code for Information Interchange) is a standard character encoding used in telecommunication. A character encoding standard that assigns unique numerical values to letters, digits, punctuation marks, and other symbols. ASCII codes are used to represent alphanumeric data.

Brief History

The code was first published as a standard in 1967. It was subsequently updated and published as ANSI X3.4-1968, then as ANSI X3.4-1977, and finally as ANSI X3.4-1986. Since it is a seven-bit code, it can at most represent 128 characters. It currently defines 95 printable characters, including 26 upper-case letters (A to Z), 26 lower-case letters, 10 numerals (0 to 9), and 33 special characters, including mathematical symbols, punctuation marks, and space characters. They represent text in telecommunications equipment and devices. These include numbers, upper and lowercase English letters, functions, punctuation symbols, and some other symbols.

In total, there are 256 ASCII characters, which can be broadly divided into three categories:

• **ASCII control characters (0-31 and 127)
• **ASCII printable characters (32-126) (most commonly referred to)
• **Extended ASCII characters (128-255)

Why do we need ASCII Value Representation?

In digital communication, computers do not understand letters and symbols like humans do. Instead, they work using binary code made up of 0s and 1s. ASCII values help convert human-readable characters into a form that computers can understand by assigning a unique number to each character.

• ASCII acts as a bridge between text and binary code.
• Each character is assigned a unique ASCII value from 0 to 127.
• Uppercase letters, lowercase letters, numbers, and symbols all have different ASCII values.
• For example, ****'A' = 65**, ****'a' = 97**, and ****'0' = 48**.

How do Computers Use ASCII to Understand Human Text?

Suppose you want to send a text message to your friend that reads, "Hello!" When you type this message on your phone or computer, each character is converted into its corresponding ASCII value. In this case, the ASCII values for "Hello!" are 72, 101, 108, 108, 111, and 33. These numerical values are then translated into binary code, which is transmitted to your friend's device. Upon receiving the message, their device converts the binary code back into ASCII values and finally displays the original text, "Hello!"

ASCII Table

So what's before 33 and beyond 126?

1. ASCII values before 32 (0-31) are control characters. A character code is often used in in-band signaling as a reference point in a set of characters to avoid adding additional symbols to the text.
2. At 32, we have space, which is included as printed characters, however, it's not wrong to say space could also serve as a control character.
3. At 127, we have DEL (delete), which is a control character.
4. After 127, (128-255), we have Extended ASCII characters representing mathematical and other symbols that are not represented as keys and are not used in general.

Below are the ASCII values of Control Characters (0-31, 127):

Difference Between ASCII and Unicode