ASCII and Unicode for Kids

1. What is ASCII?

ASCII gives every letter, number, and symbol its own special number. When you type the letter A, your computer does not store the shape of the letter. Instead, it stores the number 65. When it needs to show you that letter on screen, it looks up number 65 and draws the letter A.

There are 128 characters in ASCII, numbered from 0 to 127. That is enough for all 26 uppercase letters (A through Z), all 26 lowercase letters, the digits 0 through 9, plus punctuation marks like periods, commas, and exclamation points.

2. The History of ASCII

In the 1960s, every computer company used different numbers for letters. One company's computer might use 65 for A, while another used 193. This meant two computers could not share text files without a special translation program.

In 1963, a group of engineers in the United States created ASCII so all computers would use the same numbers. The name stands for American Standard Code for Information Interchange. Once everyone agreed on the same code, computers could finally talk to each other. You can see the key dates on our ASCII timeline.

3. How the Numbers Work

The ASCII table is like a dictionary that matches characters to numbers. Here are some examples you can look up yourself:

• Uppercase A = 65, B = 66, C = 67
• Lowercase a = 97, b = 98, c = 99
• Digits: 0 = 48, 1 = 49, up to 9 = 57
• Space = 32, exclamation mark = 33, question mark = 63

Notice a pattern? Uppercase A is 65 and lowercase a is 97. The difference is always 32. That is not a coincidence. The engineers designed it that way to make converting between uppercase and lowercase really fast for computers.

4. What Does ASCII Stand For?

Each letter in the name ASCII means something:

• American - it was created in the United States
• Standard - it is a rule that everyone agreed to follow
• Code - a set of rules for turning one thing into another
• Information - the data that computers store and share
• Interchange - exchanging data between different computers

You pronounce it "ASK-ee," rhyming with "mask" + "bee." Try saying it out loud!

5. Exploring the ASCII Table

The full ASCII table shows all 128 characters in order. You can view it as a chart (a grid with 16 columns), a compact list, or a clickable grid. Each character has its own page where you can see its number in decimal, hexadecimal, and binary.

Try the text to ASCII converter - type your name and see what numbers your computer uses to store it! Or do it in reverse with the ASCII to text tool.

6. Extended ASCII: More Characters

128 characters is not enough for languages like French (which needs e and c) or German (which needs u and ss). Extended ASCII uses 8 bits instead of 7, which doubles the range to 256 characters (0-255).

The catch: different countries created different versions. ISO 8859-1 covers Western European languages. CP437 has box-drawing characters from old DOS computers. Windows-1252 adds smart quotes. You can compare them to see how the same number maps to different characters in each version.

7. Unicode: Characters for Every Language

Even 256 characters cannot cover Chinese, Japanese, Arabic, Hindi, and all the other writing systems in the world. Unicode solves this by assigning a unique number to every character from every language. It currently includes over 154,000 characters.

Unicode includes emojis too! The smiley face, the pizza slice, the rocket - they all have Unicode numbers just like letters do. Unicode uses an encoding called UTF-8 that is smart enough to use 1 byte for ASCII characters and up to 4 bytes for complex characters like Chinese ideographs.

8. Fun with Binary

Computers do not actually store the number 65 in decimal. They use binary, a number system with only two digits: 0 and 1. In binary, the number 65 is written as 1000001. Each 0 or 1 is called a "bit," and ASCII uses 7 bits per character.

Want to see how it works? Use the binary to ASCII converter to turn binary numbers into text. Or try the base converter to switch between decimal, binary, hexadecimal, and octal number systems.

9. ASCII Art

You can make pictures using only text characters! This is called ASCII art. Artists arrange letters, numbers, and symbols to create images of animals, faces, buildings, and more.

Check out the ASCII art gallery for examples, or try the emoticons collection for text faces like the shrug and table flip. You can create your own ASCII art banner with our ASCII art generator, or turn a photo into character art with the image to ASCII converter.

10. Fun Facts

1. The first 32 ASCII characters are invisible control characters. Code 7 (BEL) used to make old computers beep!
2. The space character is not "nothing" - it is ASCII code 32 and takes up exactly the same amount of storage as any letter.
3. NASA's Apollo guidance computers used ASCII to communicate with Mission Control during the 1969 moon landing.
4. The @ symbol (ASCII 64) was chosen for email addresses by Ray Tomlinson in 1971 because nobody used it for anything else.
5. Unicode includes Egyptian hieroglyphs, musical notation, Braille patterns, and domino tiles - not just letters and emojis.
6. Every web page you visit uses UTF-8 encoding, and the first 128 characters of UTF-8 are exactly the same as ASCII.