What Are Alphanumeric Characters?

Alphanumeric Characters: Since computers (or central processing units, to be specific) use machine language in the form of numbers to communicate, computer programmers need to write their instructions using numbers rather than alphabet characters. To do this, programmers use numeric representations of what humans see as alphabet characters. You’ve probably seen or heard of binary code which uses only 0s and 1s to represent an alphanumeric character. Computer programmers can use a series of 0s and 1s to represent any character they wish. For example, in binary, the letter ‘A’ would be written as 01000001.

Another way computer programmers represent alphanumeric characters is to use ASCII. ASCII stands for American Standard Code for Information Interchange.

Now, you are probably thinking to yourself, ‘I can key those numbers from my keyboard or number pad, and all I get are numbers!’ You would be correct. In order to use those numbers as ASCII code, you need to be using a text-only program such as Notepad (or save a Word document as text only by choosing the plain text option).Using the ASCII table, a computer programmer can represent the word ‘red’ using the numbers 82 69 68. This is true unless they wanted it in lower case letters, in that case it would be 114 101 100.

What Are Alphanumeric Characters?
In some usages, the alphanumeric character set may include both upper and lower case letters, punctuation marks and symbols (such as @, &, and *, for example). For languages other than English, alphanumeric characters include letter variations such as é and ç.

The following characters are considered to be punctuation: ! @ # & ( ) – [ { } ] : ; ‘, ? / * Nonalphanumeric characters that are considered to be symbols are also treated as white space.

The login name must start with an alphabetic character and can contain only alphanumeric characters and the underscore ( _ ) and dash ( – ) characters. Full name can contain only letters, digits, and space, underscore ( _ ), dash ( – ), apostrophe ( ‘ ), and period ( . ) characters.

What Are Alphanumeric Characters

(ALPHAbeticNUMERIC) The combination of alphabetic letters, numbers and special characters such as in a mailing address (name, street, city, state, zip code). The text in this encyclopedia and every document and database is alphanumeric. See alphanumerish and special character.

Alphanumeric Characters List

Alphanumeric, also known as alphameric, simply refers to the type of Latin and Arabic characters representing the numbers 0 – 9, the letters A – Z (both uppercase and lowercase), and some common symbols such as @ # * and &.

Sites requesting that you create an alphanumeric password are asking us to use a combination of numbers and letters, which creates stronger passwords. We also use alphanumeric keys to create file names, although there are some symbols that are not accepted as part of a file name, such as a slash (/).

That doesn’t seem very secret does it? The ‘secret’ language part comes into play when we start talking about alphanumeric characters in terms of actual computer programming.

Partial ASCII Table


What Is Alphanumeric Characters

Alphanumeric, also referred to as alphameric, is a term that encompasses all of the letters and numerals in a given language set. In layouts designed for English language users, alphanumeric characters are those comprised of the combined set of the 26 alphabetic characters, A to Z, and the 10 Arabic numerals, 0 to 9.

For some computer purposes, such as file naming, alphanumeric characters are strictly limited to the 26 alphabetic characters and 10 numerals. However, for other applications, such as programming, other keyboard symbols are sometimes permitted. In some usages, the alphanumeric character set may include both upper and lower case letters, punctuation marks and symbols (such as @, &, and *, for example). For languages other than English, alphanumeric characters include letter variations such as é and ç.

The mishmash of letters and numerals used for texting abbreviations is sometimes referred to as alphanumerish. As is the case with the term alphanumeric, alphanumerish can be expanded to include other characters. The grawlix, for example, which represents a non-specific profanity, is generally made up of typographical symbols that do not include either letters or numerals, but it might be considered an alphanumerish word nevertheless.

Alphanumeric Characters Meaning

When a string of mixed alphabets and numerals is presented for human interpretation, ambiguities arise. The most obvious is the similarity of the letters IO and Q to the numbers 1 and 0. Therefore, depending on the application, various subsets of the alphanumeric were adopted to avoid misinterpretation by humans.

In passenger aircraft, aircraft seat maps and seats were designated by row number followed by column letter. For wide bodied jets, the seats can be 10 across, labeled ABC-DEFG-HJK. The letter I is skipped to avoid mistaking it as row number 1.

In Vehicle Identification Number used by motor vehicle manufacturers, the letters IO and Q are omitted for their similarity to 1 or 0.

Tiny embossed letters are used to label pins on an V.35/M34 electrical connector. The letters IOQS and Z were dropped to ease eye strain with 1053,and 2. That subset is named the DEC Alphabet after the company that first used it.

For alphanumerics that are frequently handwritten, in addition to I and OV is avoided because it looks like U in cursive, and Z for its similarity to 2.

Alphanumeric Characters Example

Alphanumeric: consisting of or using both letters and numerals.


  1. 6 Characters: name18
  2. 7 Characters: nameK18
  3. 8 Characters: myname18
  4. 9 Characters: mynameK18
  5. 10 Characters: myname2018
  6. and so on…..

The question should not be like how to create alphanumeric password but why this is required?

Ans: Use of such pattern increase the characters domain and so the search domain for the brute force or other password attacks get increased which makes such passwords computationally secure.

For example: If you only use lower case letters for a 6 char long password then the attacker only have to try 26^6 but if you use both upper and lower case letters then the search space become 52^6, likewise if numeric chars are used then 62^6 and if special chars are allowed then the further it will increase. So length of password also do the same things.

for a 7 chars long password: 62^7 and likewise…

One must remember all these are just computationally secure means password can’t be break with available computation in a feasible time. Who knows what future holds.