Why do you need it? Sizing Exchange can be a bit of a black art. understanding your users, how they’re using mail, understanding the disk I/O parameters of the disks in your SAN or direct attached disks all add up to spending a fair amount of time working out how to size the mailbox role required for the version of Exchange you’re using.
The Role Requirements calculators for Exchange are updated regularly as the team takes feedback and adjusts the calculator accordingly, so check back every time you need to calculate the role requirement for a new server.
The blog post describing the new release of the calculator is here:
The download link for the calculator is here: