Microsoft has announced the Exchange 2019 Sizing Calculator. As with Exchange 2016 and earlier versions, this is an Excel file that can be used to calculate the hardware requirements for new Exchange 2019 installations.
Unfortunately, the Sizing Calculator cannot be downloaded, but will be included in the ISO file together with the upcoming CU2 for Exchange 2019. Unfortunately, the Sizing Calculator will no longer be available for download, for which Microsoft gives the following reason:
Moving this to the .ISO will allow us to update the calculator more readily and more frequently, as well as ensure it is aligned with any future investments in Exchange Server.
Source: Announcing The Exchange Server 2019 Sizing Calculator
I also had to smile a little at this reason: Couldn't Microsoft think of a better way than to put a small Excel file in an ISO?
The complete announcement of the Exchange Team can be found in the article linked above. Incidentally, the link leads to the new home of the Exchange Team blog, which also needs a bit of work. At least the current design looks somewhat unfinished:
Also, some functions do not seem to work properly yet. For example, clicking on an image only opens a small version of the image, enlarging it or displaying it in its original size does not work at the moment:
The small problems will certainly be fixed, maybe even the Sizig Calculator will be offered for download...