Short Answer:  Check out the Windows Server Virtualization Calculator, fill in how many servers, VMs and Processors you own; and it will tell you which server licenses you should buy.

Long Answer: Ok, so we all know licensing is a lot of pain.  The question on everybody’s lips is “What point does a license for Datacenter become more cost effective than multiple copies of R2?“

Enter the Windows Server Virtualization Calculator hereby referred to as WSVC — and using the defaults the answer: 16x VMs on a quad CPU box is the break even.

There is no hard and fast rule (enter the Blades vs Beefy Boxes debate) but the WSVC does a very nice job of  crunching some of the numbers.  The costs are in RRP USD.

Cool huh?