A special character is one that is not considered a number or letter. Symbols, accent marks, and punctuation marks are considered special characters. Similarly, ASCII control characters and formatting characters like paragraph marks are also special characters. Unlike alphanumeric characters, special characters are extremely versatile and can be used for a number of different purposes in writing, coding, and mathematical operations.
Examples of special characters
On a typical U.S. QWERTY keyboard, there are 32 special characters. These are listed in order of appearance from left to right in the table below:
|
Character |
Description |
Use |
|
~ |
Tilde |
Accent mark commonly used in Spanish |
|
` |
Grave accent |
Accent mark commonly used in French |
|
! |
Exclamation point |
Expressing strong emotion in written language; expressing logical negation in programming languages; noting factorial operation in mathematics |
|
@ |
Ampersat |
Connecting usernames to domain names in email addresses; expressing rates in accounting and invoicing; preceding usernames/handles on social media platforms and chat rooms |
|
# |
Octothorpe |
Number sign; expressing non-executable statement in programming |
|
$ |
Dollar sign |
Expressing value in currency |
|
% |
Percent sign |
Expressing value in percentages |
|
^ |
Circumflex, caret |
Expressing exponents in mathematics; shorthand for CTRL key on PCs |
|
& |
Ampersand |
Symbolizing “and” in English text; combining values in spreadsheet formulas |
|
* |
Asterisk |
Mathematical multiplication; indicating footnotes |
|
( |
Open parenthesis |
Beginning parenthetical text |
|
) |
Close parenthesis |
Ends parenthetical text |
|
_ |
Underscore |
Alternative to space key when spaces are not allowed |
|
– |
Hyphen, dash |
Mathematical subtractions; creating en dashes or em dashes in written text |
|
+ |
Plus sign |
Mathematical additions |
|
= |
Equal sign |
Mathematical equations |
|
{ |
Open brace |
Opening groups of statements or blocks of code in various programming languages |
|
[ |
Open bracket |
Beginning section of missing details in quoted text; beginning string validation in programming languages; beginning mathematical notation for intervals |
|
} |
Close brace |
Closing groups of statements or blocks of code in various programming languages |
|
] |
Close bracket |
Ending section of missing details in quoted text; ending string validation in programming languages; ending mathematical notation for intervals |
|
| |
Vertical bar |
Delimiter in text files; redirecting a command’s output to the input of another in a command line interface (CLI); representing an OR boolean operator (double pipe) |
|
|
Backslash |
Separating locations in a file or network path |
|
: |
Colon |
Separating the protocol from a web address in a URL; identifying a range in a spreadsheet formula; preceding a list of items in written text |
|
; |
Semicolon |
Joining two related sentences in written text; finishing an instruction in programming languages; separating long items in a list in written text |
|
“ |
Double quotation mark |
Indicating a verbatim transcription of something that has been written or spoken; identifying text or data that is not part of a programming command or HTML tag |
|
‘ |
Single quotation mark, apostrophe |
Containing commands or literal strings; indicating a quotation within a quotation; expressing a contraction or possessive noun in written text |
|
< |
Open angle bracket, less than symbol |
Expressing the relationship between two values in which the one on the right is greater than the one on the left |
|
, |
Comma |
Separating items in a list; joining independent clauses or sentences with a conjunction; separating digits in large numbers; separating values or elements in a computer program |
|
> |
Close angle bracket, greater than symbol |
Expressing the relationship between two values in which the one on the left is greater than the one on the right |
|
. |
Period |
Indicating the end of a declarative sentence; separating a file name from the file extension; separating sections of a URL |
|
? |
Question mark |
Asking a question |
|
/ |
Forward slash |
Mathematical division; separating month, day, and year of a date; signifying non-executable statements in programming languages; closing tags in HTML and XML; delimiting expressions; separating locations in a file or network path; writing URLs and network addresses |
Special characters in passwords
Special characters are often required when creating a strong password. This is because they add complexity to the password and reduce the chances that the user’s account will be hacked. Many hackers use lists of common or easily guessed phrases and combinations of characters (such as “password” and “1234”) to gain access to a user’s account, so special characters make the password less predictable. However, special characters that are used in predictable ways (like replacing “a” with “@” or “s” with “$”) have lost their effectiveness when it comes to password strength.
