You will naturally like to see what equipment you need and what enhancements you can make with these needs before you invest for a new vSan Environment
There are several manufacturer tools that I share links with below that you can perform automatically.
Click here for vSan Readynode Sizer and here for Vxrail Xpress Sizer.
So what should you do if you want to do an average calculation without having to depend on these tools?