Recently, My laptop battery is not lasting long. So to find out how long its working, I wanted uptime command was veryhandy on FreeBSD/Linux. But on windows, I was not able to find any tool that works like this. One option is to use

Systeminfo | Find "Up Time"

It takes a little time, but works, if want it as a command, save it as a .bat to your WINDOWS directory.

If you want the uptime command from Microsoft – here’s the link for it: uptime.exe