Follow the instruction to figure out where to look for Base records number:
Sing into Base account and click on the module you want to count. For example, press ‘Contacts’ on the dashboard. In order to see a total amount of items you have, click on the box above ‘All Contacts'.
2. Now, you are able to see a total of your records.
In a similar way you may easily count the rest of your data. Then make your migration estimation, using calculator.