Custom summary formulas are a powerful reporting technique, but they can be tricky. Here are some tips to keep in mind when working with them.

Available in: both Salesforce Classic and Lightning Experience |

Available in: **Group**, **Professional**, **Enterprise**, **Performance**, **Unlimited**, and **Developer** Editions |

Functions for use with custom summary formulas in reports are available under the function category. Select a function, then click **Help on this function** for information.

- A summary formula can't reference another summary formula.
- Regardless of the summary formula data type, your summary formula can contain fields of different data types, including: number, currency, percent, and checkbox (true/false) fields. For example, a summary formula in an Opportunities with Partners report can reference opportunity Amount or Stage Duration, as well as account Annual Revenue.
- Dashboard and report charts that display values from custom summary formulas display decimal places using your default currency setting instead of what you specified for the formula. For example, if the summary formula specifies zero decimal places, no decimal places appear in columns, but chart values show the number of decimal places specified for your default currency (usually two decimal places). This applies to currencies, numbers, and percentages.
- When a field is deleted or is unavailable (for example, because of field-level security), all custom summary formulas that contain the field are removed from the report.
- The summary types Sum, Largest Value, Smallest Value, and Average are not available for use with the Record Count field.
- The Smallest Value summary type includes blank (null) or zero values in the summary formula calculation if these values are present in your report data.
- The Largest Value summary type includes the largest blank (non-null) value present in your report data.
- Percents are represented as decimals in summary formulas. 20% is represented as 0.20.
- Operators can be used to give fields in summary formulas a negative value. For example: {!EMPLOYEES:SUM} + - {!SALES:SUM}.
- For custom summary formulas on matrix reports, Salesforce calculates results for all formulas where the Where will this formula be displayed? option is not set to All summary levels. The formula determines the value returned. If null is returned, the cell will be empty.
- Summary fields on tabular, summary, and matrix reports can display up to 21-digits. Summary fields of 21 digits will display precisely, but more than 21 digits may not be precise. If “#Too Big!” appears in report cells, check your formula for calculations that could result in more than 18 digits. Avoid multiplying large numbers, raising a large number to a power, or dividing by a very small number.
- Formulas treat blank (null) report cells as zero values.
- “#Error!” displays on report cells whenever an error occurs while calculating a formula’s value. “#Error!” also displays when formulas divide by zero. To resolve the error, check your formula and provide an alternative value.
- Cross-block custom summary formulas are available for joined reports.