Alt key

However, in modern software, due to the requirement for all bits to be used for post-ASCII 8-bit character sets, Alt no longer works in such a way.

Since the 1990s, Alt has been printed on the Option key (⌥ Opt) on most Mac keyboards.

Alt is used in non-Mac software, such as non-macOS Unix and Windows programs, but in macOS it is always referred to as the Option key.

For example, holding down Alt while typing 0225 (Alt+0225) on the numeric keypad will result in á, the character at 225 in the (Western Latin) code page 1252.

These extended keyboard characters are useful for persons using foreign languages, mathematics, currency symbols, business use, etc.

The diagram below shows the special characters a US Mac keyboard will produce when the Option key is pressed.

When a user presses the Alt key by itself on Microsoft Windows, that moves keyboard focus to the menu bar of the application having keyboard focus, and the key is not delivered to the application.

The Alt key on a Lenovo laptop keyboard
ISO keyboard symbol for “Alternate”
The Alt key on an Apple keyboard
Tilde Exclamation mark At sign Number sign Dollar sign Percent sign Caret Ampersand Asterisk Parenthesis Parenthesis Underscore Plus sign Backspace Backtick 1 (number) 2 (number) 3 (number) 4 (number) 5 (number) 6 (number) 7 (number) 8 (number) 9 (number) 0 Hyphen-minus Equals sign Backspace Tab key Q W E R T Y U I O P Curly bracket Curly bracket Vertical bar Tab key Q W E R T Y U I O P Square bracket Square bracket Backslash Caps lock A S D F G H J K L Colon (punctuation) Quotation mark Enter key Caps lock A S D F G H J K L Semicolon Apostrophe Enter key Shift key Z X C V B N M Bracket Bracket Question mark Shift key Shift key Z X C V B N M Comma (punctuation) Full stop Slash (punctuation) Shift key Control key Windows key Alt key Space bar Alt key thumb Menu key Control key