Add a total to a group or tablix in a paginated report (Report Builder)
Applies to: 
Microsoft Report Builder (SSRS)
Power BI Report Builder
Report Designer in SQL Server Data Tools
In a paginated report, you can add totals in a tablix data region for a group or for the entire data region. By default, a total is the sum of the numeric, non-null data in a group or in the data region, after filters are applied. To add totals for a group, select Add Total on the shortcut menu for the group in the Grouping pane. To add totals for an individual cell in the tablix body area, select Add Total on the shortcut menu for the cell. The Add Total command is context-sensitive and enabled only for numeric fields. Depending on the tablix cell that you select, you can add a total for a single cell by selecting a cell in the tablix body area. Or, you can select the entire group by selecting a cell in the tablix row group area or the tablix column group area. For more information about tablix areas, see Tablix data region (Report Builder).
After you add a total, you can change the default function Sum to a different aggregate function from the list of built-in report functions. For more information, see Aggregate functions reference (Report Builder). You can create and modify paginated report definition (.rdl) files in Microsoft Report Builder, Power BI Report Builder, and in Report Designer in SQL Server Data Tools.
Add a total for an individual value in the tablix body area
In the tablix data region body area, right-click the cell where you want to add the total. The cell must contain a numeric field. Point to Add Total, and then select Row or Column.
A new row or column outside the current group is added to the data region, with a default total for the field in the cell you clicked.
If the tablix data region is a table, a row is automatically added.
Add totals for a row group
In the tablix data region row group area, right-click a cell in the row group area for which you want totals, point to Add Total, and then choose Before or After.
A new row outside the current group is added to the data region, and then a default total is added for each numeric field in the row.
Add totals for a column group
In the tablix data region row group area, right-click a cell in the column group area for which you want totals, then point to Add Total, and choose Before or After.
A new column outside the current group is added to the data region, and then a default total is added for each numeric field in the column.