How do I find my operating system (OS) version?

How do I find my operating system (OS) version on a Mac?

Follow these two easy steps to determine which version of the operating system is installed on your Mac.

  1. From the Apple menu, select About This Mac.
  1. The resulting window shows your operating system version. In this example, you are using Mac OS X 10.5.3.

How do I find my operating system (OS) version on a PC?

Follow these three easy steps to determine which version of the operating system is installed on your PC.

  1. On the taskbar at the bottom of your screen, click Start or the Windows logo. If your menu has a 'Start Search' field, continue to step 2a. Otherwise, click Run and continue to step 2b.
  1. Search or Open
    1. In the Search box, type winver. Double-click winver.exe from the results and continue to step 3.
    2. In the Open box, type winver and then click OK.
  1. The resulting window shows your operating system version. In this example, you are using Windows Vista SP1.