# Alphanumeric

Updated: 02/04/2024 by Computer Hope

Alphanumeric or alphameric describes data that's both letters (A to Z in English) and numbers (0 to 9). For example, "1a2b3c" is a short string of alphanumeric characters. Alphanumeric is commonly used to help explain the availability of text entered or used in a field, such as an alphanumeric password field.

Tip

A character that's not a letter or number, like an asterisk (*), is considered a non-alphanumeric character. If a password requires only alphanumeric characters, it must be only letters and numbers with nothing else (sometimes a space may not be supported).

Note

In some situations, punctuation marks may be included as part of alphanumeric characters.

## Examples of alphanumeric and non-alphanumeric

Below are more examples of alphanumeric and non-alphanumeric text.

`My PO Box number is 1236`

This first example is alphanumeric because it contains letters and numbers. It doesn't matter if letters are uppercase or lowercase; the string is considered alphanumeric as long as the text includes numbers.

Note

`Nathan is number one`

This second example is non-alphanumeric. Although it says "one," it is written out and contains no numbers.

`secretpassword123`

The third example is a valid alphanumeric password, as it contains only letters and numbers.

`\$ecret!Passw0rd`

This last example of a password would be considered non-alphanumeric because it contains characters that are not letters or numbers.

## How many alphanumeric characters are there?

In English, counting each letter (A to Z) gives you 26 characters; with the additional nine numbers, you get a total of 35 characters.

## Why are alphanumeric keys scattered?

See our QWERTY page for further information on why the keyboard's keys are not in alphabetical order.

## Alphanumeric characters, special characters, and national characters

In English, alphanumeric characters are the letters "A" through "Z" and numbers from "0" to "9." However, it's important to realize that other languages may include what English considers special characters as part of their language. Also, national characters are letters with accent marks or other symbols; these characters are often not considered alphanumeric in English.

## Do file names support more than alphanumeric characters?

Yes. Most operating systems and programs support many of the available characters and symbols found on a keyboard. However, some characters are reserved characters that cannot be used. For example, the forward slash and backslash characters are usually reserved characters and a file name cannot include them.

## What is alphanumeric order?

An alphanumeric order or alphanumeric sort is a method of sorting data, often in the following order.

`punctuation mark, numbers, capital letters, lowercase letters, and symbols.`
Note

The order example above is the same as how characters are listed in the ASCII (American Standard Code for Information Interchange) chart.

## Is there an alphanumeric keypad?

No. There's a numeric keypad. However, this keypad only has numbers and other symbols, not letters.

## What is alphanumerish?

Alphanumerish describes chat slang that shortens words using numbers instead of words. Common examples are "some1" for "someone," "2day" for "today," and "u2" for "you too."