Reducing File Sizes for Workbooks with PivotTables

PivotTables are great for certain types of data analysis. Since PivotTables do quite a bit of number crunching, one of the techniques Excel uses to process them faster is to create an “intermediate dataset” to work with. This intermediate dataset, by default, is stored with the worksheet, so PivotTables can increase the size of your workbooks, sometimes dramatically.

If your workbook contains multiple PivotTables, all based on a single data source, Excel may create an intermediate dataset for each PivotTable, instead of using one intermediate dataset. This, of course, could increase the size of your workbook very rapidly.

You can control how Excel creates the intermediate dataset by modifying the options you use when you create the PivotTable.

  1. Create your PivotTable as you normally would.
  2. Display the Options tab (Excel 2007 and Excel 2010) or the Analyze tab (Excel 2013) of the Ribbon. (This tab is visible only when you select a cell in the PivotTable.)
  3. At the left end of the Ribbon click the Options tool in the PivotTable group. Excel displays the PivotTable Options dialog box.
  4. Make sure the Data tab is displayed. (See Figure 1.)
  5. Figure 1. The Data tab of the PivotTable Options dialog box.

  6. Clear the Save Source Data with File check box.
  7. Choose the Refresh on Open check box.
  8. Click on OK to close the PivotTable Options dialog box.

You don’t need to choose the Refresh on Open check box (step 6) if you don’t want to, but if you don’t, you will need to remember to manually refresh the PivotTable every time you open the workbook.

If you already have quite a few PivotTables in your workbook, and you don’t want to go through the process of creating them again, you can use a macro to step through the PivotTables and modify the caching index and turn off the saving of the intermediate data to disk. The following macro will accomplish these tasks:

Sub PTReduceSize()
    Dim wks As Worksheet
    Dim PT As PivotTable

    For Each wks In ActiveWorkbook.Worksheets
        For Each PT In wks.PivotTables
            PT.CacheIndex = 1
            PT.SaveData = False
End Sub

Once the macro runs (it won’t take long), you should save your workbook using the Save As option. This will write a new workbook file, and you will be able to compare how much this change reduced the size of your workbook. Remember, however, that with the intermediate data not being saved to disk, the refreshing of the PivotTables takes longer when you first open the workbook.