ChevUribeChevUribeChevUribe
Not that I know of any sort of capacity planner tool on the market, but there is guide for you for your consideration from physical server to VM,
1) Before conversion you need to prepare the same size of CPU/RAM/Disk at the target VM server.
2) You are recommended to reserve more than 1.5x of original size of your physical disk size in source server during the P2V convert process.
3) After your physical server migrated to target VM server, you are recommended to spare 1.5x additional disk size for VM memory management of the VM guest.
That is about it and hope to help you.
Xlord