How does everyone count the total amount of GHz for VMs on a host \ cluster?

Hello,

I want to do some basic sizing and I may\may not be going the write way about it.  Say for example I have a 4 node cluster with a total of 200GHz and 1TB of RAM across all four hosts with 100 VMs.  How can I get the total amount of GHz\Memory that each VM is configured with (not necessaryly using in real time) so I can workout or demonstrate what will fit onto one or two hosts in the cluster for example?

Thanks for your help and advice in advance,