What are the F1 through F12 keys?

Commonly known as function keys on a computer keyboard, F1 through F12 may have a variety of different uses or no use at all. The operating system installed on the computer and the software program currently open can change how each of these keys operate. A program is capable of not only using each of the function keys, but also combining the function keys with the ALT or CTRL key. For example, Microsoft Windows users can press ALT + F4 to close the program currently active.
Note: Some keyboards include additional functions on the function keys, which can be activated by pressing the FN key, usually located near the CTRL key, and the appropriate function key. The additional functions available with the use of the FN key will differ depending on the type and brand of keyboard being used. Please check your computer's documentation or manufacturer's website for specific details on which features are available on your keyboard function keys with the use of the FN key.
Tip: Some computers may automatically enable the FN key for accessing the special functions on the F1 through F12 keys. You may be able to turn off the FN key by accessing the keyboard settings in the Control Panel.
If your keyboard does not have a row of function keys, they are probably set up as secondary functions on other keys. Some laptop keyboards are set up this way to save space. They can be activated by pressing another key plus the key with the secondary F key functionality.
Below is a listing of some of the more common functions of the functions keys for Microsoft Windows and Microsoft applications, as well as some for Mac OS. As mentioned above, not all programs support these function keys and the function keys on your keyboard may perform different tasks then those mentioned below.
Tip: If you are looking for specific shortcut keys and function key examples, please visit our shortcut key page.
F1
Almost always used as the help key, almost every program opens a help screen when this key is pressed.
Enter CMOS Setup.
Windows Key + F1 would open the Microsoft Windows help and support center.
Open the Task Pane.
F2
In Windows renames a highlighted icon, file, or folder in all versions of Windows.
Alt + Ctrl + F2 opens document window in Microsoft Word.
Ctrl + F2 displays the print preview window in Microsoft Word.
Quickly rename a selected file or folder.
Enter CMOS Setup.
F3
Often opens a search feature for many programs including Microsoft Windows when at the Windows Desktop.
In MS-DOS or Windows command line F3 will repeat the last command.
Shift + F3 will change the text in Microsoft Word from upper to lower case or a capital letter at the beginning of every word.
Windows Key + F3 opens the Advanced find window in Microsoft Outlook.
Open Mission Control on an Apple computer running Mac OS X.
F4
Open find window in Windows.
Open the address bar in Windows Explorer and Internet Explorer.
Repeat the last action performed (Word 2000+).
Alt + F4 closes the program window currently active in Microsoft Windows.
Ctrl + F4 closes the open window within the current active window in Microsoft Windows.
F5
In all modern Internet browsers, pressing F5 will refresh or reload the page or document window.
Open the find, replace, and go to window in Microsoft Word.
Starts a slideshow in PowerPoint.
F6
Move the cursor to the address bar in Internet Explorer, Mozilla Firefox, and most other Internet browsers.
Ctrl + Shift + F6 opens to another open Microsoft Word document.
Reduce laptop speaker volume (on some laptops).
F7
Commonly used to spell check and grammar check a document in Microsoft programs such as Microsoft Word, Outlook, etc.
Shift + F7 runs a Thesaurus check on the word highlighted.
Turns on Caret browsing in Mozilla Firefox.
Increase laptop speaker volume (on some laptops).
F8
Function key used to enter the Windows startup menu, commonly used to access Windows Safe Mode.
Used by some computers to access the Windows recovery system, but may require a Windows installation CD.
Displays a thumbnail image for all workspaces in Mac OS.
F9
Refresh document in Microsoft Word.
Send and receive e-mail in Microsoft Outlook.
Opens the Measurements toolbar in Quark 5.0.
Reduce laptop screen brightness (on some laptops).
With Mac OS 10.3 or later, displays a thumbnail for each window in a single workspace.
Using the Fn key and F9 at the same time opens Mission Control on an Apple computer running Mac OS X.
F10
In Microsoft Windows activates the menu bar of an open application.
Shift + F10 is the same as right-clicking on a highlighted icon, file, or Internet link.
Access the hidden recovery partition on Compaq, HP, and Sony computers.
Enter CMOS Setup on some computers.
Increase laptop screen brightness (on some laptops)
With Mac OS 10.3 or later, shows all open Windows for the active program.
F11
Enter and exit full screen mode in all modern Internet browsers.
Ctrl + F11 as computer is starting to access the hidden recovery partition on many Dell computers.
Access the hidden recovery partition on eMachines, Gateway, and Lenovo computers.
With Mac OS 10.4 or later, hides all open windows and shows the Desktop.
F12
Open the Save as window in Microsoft Word.
Ctrl + F12 opens a document In Word.
Shift + F12 saves the Microsoft Word document (like Ctrl + S).
Ctrl + Shift + F12 prints a document in Microsoft Word.
Preview a page in Microsoft Expression Web.
Open Firebug or browser debug tool.
With an Apple running Mac OS 10.4 or later, F12 shows or hides the Dashboard.
Access the list of bootable devices on a computer at startup, allowing you to select a different device to boot from (hard drive, CD or DVD drive, floppy drive, USB drive, and network).