How beefy of an server do you need to host minecraft?

I feel like spinning up my old PC's to host some minecraft games to my friends but I'm not sure if the performance is high enough.. Last time I did it we ran on Pentium 4's and that was ..an experience.

Really you dont need much as long as you have a good connection from the computer to the internet so peoples pings arent shit and whatever.
it also depends on the type of server

dont try to make a Server on your PC you Need good Internet for that, and if you dont have min: 16 GB Ram Forget it