uptime is a simple utility for Windows that can be used to quickly find out how long it's been since the last restart. The easiest way to see how long the current system uptime is on Windows XP, Windows Vista, Windows 7, Windows 8, and Windows 10 is simply to double-click on uptime.exe and see the results.

uptime has no requirements and can be used without installation. For further information, refer to the official release information.