When a Custom Summary Formula is added to a Salesforce Report, the value in the Grand Total row may not match the sum of the formula values shown for each grouping. This is expected behavior because the Grand Total is not calculated by adding the grouped formula values together. Instead, Salesforce recalculates the formula independently at runtime using the overall dataset.
Additionally, Smart Totaling can also cause differences when currency conversion is involved.
This article explains why this behavior occurs and provides an example using a Custom Summary Formula in an Opportunity report.
The Grand Total for a Custom Summary Formula is calculated independently at runtime against all records included in the report. It is not the sum of the formula values displayed in each grouping. This behavior is expected and is by design.
Another reason for a mismatch is Smart Totaling, particularly when currency conversion is used. For more information, see Report total doesn't match the total in Excel or in a Dashboard table component.
Example Custom Summary Formula added to an Opportunity report:
IF(AMOUNT.CONVERT:SUM < 0, 0, AMOUNT.CONVERT:SUM)
Report setup
Format: Summary Report
Grouping 1: Account Name
Grouping 2: Opportunity Owner
Report data
One Opportunity for UserA with a converted amount of -365.25
Two Opportunities for UserB with a total converted amount of 401
What the report shows
For UserA, the converted amount is negative, so the formula evaluates to 0.
For UserB, the converted amount is positive, so the formula displays 401.
For the Grand Total, Salesforce recalculates the formula using the combined Opportunity amounts (300 + 101 - 365 = 36). Since the overall total is greater than zero, the formula returns 36, rather than the sum of the grouped formula values (0 + 401 = 401).
Image alt text
"Screenshot showing a summary report with two groupings—Account Name and Opportunity Owner—where the Grand Total row displays a different value than the sum of the Custom Summary Formula column for the individual groupings."
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