VertiPaq Analyzer is useful to analyze VertiPaq storage structures for a data model in Analysis Services Tabular.
A complete description and short tutorial is available in the article Data Model Size with VertiPaq Analyzer.
You can analyze a Power Pivot data model by restoring it in Analysis Services.
The current version is not compatible with the Power BI Designer data model.
UPDATE 2015-09-27: Version 1.3 now handles correctly renamed tables and renamed columns in the data model.
UPDATE 2015-11-26: Version 1.4 now includes encoding type and it fixes column names if they have been renamed in the data model.
UPDATE 2015-12-31: Version 1.5 fixed a small issue displaying the combination of table-column name in a single column, which was displaying column id instead of column name in ColumnKey attribute. Now we use TableColumn attribute in Columns worksheet.
UPDATE 2016-06-26: VertiPaq Analyzer does not report correctly the column size for database in compatibility model 1200 deployed in Analysis Services 2016 RTM (build 13.0.1601.5) – this is caused by a bug in Analysis Services, we are waiting for a fix from Microsoft.
UPDATE 2016-08-28: Version 1.6 fixed an issue displaying column’s cardinality in Columns worksheet. Microsoft fixed the issue of compatibility models 1200 in Power BI Version 2.38.4491.282 (August 2016). Still waiting for a fix for Analysis Services 2016 RTM.
UPDATE 2016-09-22: Microsoft fixed the bug of DMV in SQL Server 2016 RTM CU2. Now VertiPaq Analyzer 1.6 works correctly also with SSAS Tabular models in compatibility level 1200.