How do we calculate the database size?

Hi Team,

One of our customer trying to find resources on TechNet that cover storage requirements for the following elements: 

•         Databases:

Back End

Monitoring

Archiving

Persistent Chat

•         Lync File Share
•         CLS Logging 

We can find information for estimating the Monitoring\Archiving database sizes using the user modelshttps://technet.microsoft.com/en-us/library/gg615015(v=ocs.15).aspx but not much else that is published on TechNet.

How do we calculate the database size for the above databases? 

Many thanks,