Common Alt codes entered on a computer keypad include the symbols for dollars, cents and percent. The Alt code for the dollar sign is 36, the Alt code for the percent sign is 37, and the Alt code for the cents sign is 155.
Alt codes present typists with a shortcut for inserting symbols while working on a computer. The keyboard must have a separate number pad with a number lock. To insert these symbols, typists have to hold down the Alt key while typing in the code on the number pad.
A common usage of Alt codes is using them to insert letters with accents for foreign languages. For example, the Alt code 0192 inserts an accented capital "A," À. The Alt code 0241 inserts a lowercase "n" with a tilde, ñ. The Alt code 0252 inserts a lowercase "u" with umlauts, ü.
Typists can also use Alt codes for other foreign characters, such as the upside down marks used in Spanish. For the Spanish exclamation mark, the Alt code is 0161, while 0191 is the code for the Spanish question mark. The Alt code for Spanish and French quotation marks is 0171.
It's also possible to use Alt codes to insert fun symbols. For example, the Alt code 1 inserts a smiling face. The Alt code 14 is for music notes, and Alt code 15 is for sunshine.