Some list views provide additional functionality to calculate totals by selected rows. For example, this functionality is available in a list of jobs, projects, invoices, quotes.
To use it, select any number of rows in the list. Below the table with rows, you will find additional label showing you total by selected rows:
This row will display total amount of selected documents, as well as totals by currencies, if selected rows contain different currencies.
This functionality works even if you select rows on multiple pages. You can switch pages and select additional rows by holding Ctrl button.