Quick, clean, and to the point

Sum formulas only

Excel formula: Sum formulas only
Generic formula 

To sum values created by formulas only, you can use a formula based on the SUMPRODUCT and ISFORMULA functions. In the example shown, the formula in F6 is:


where sales is the named range C5:C16. The result is $5950, the sum of the values in the range C13:C16, which are created with a formula.


In this example, the goal is to calculate a sum of the values in a range that are generated with a formula. In other words, we want to sum values in a range while ignoring the values that have been entered manually. In the context of this example, the hardcoded values in C5:C12 represent actual sales values and the values in the range C13:C16 represent forecasted values. This problem can be solved with a formula based on the SUMPRODUCT and ISFORMULA functions, as explained below.

Forecasted values

The forecasted values in the range C13:C16 are created with a formula based on the MROUND function. The formula in C13, copied down, is:


This formula is used generate values that are 5% higher than the previous month, rounded to the nearest multiple of 25.

Sum formulas

To sum values in the range C5:C16 that are created with formulas, the formula in F6 is:


This formula uses boolean logic to "filter" the numbers in sales (C5:C16) based on whether the values come from a formula or not. The ISFORMULA function created the filter like this:


ISFORMULA returns TRUE when cell contains a formula, and FALSE if not. In this case, there are 12 values in the range C5:C16, so ISFORMULA returns 12 results in an array like this:


Each TRUE value in this array represents a cell that contains a formula. Notice the last 4 values are TRUE. When this array is multiplied by the named range sales (C5:C16), the math operation coerces the TRUE and FALSE values to 1s and 0s. We can visualize the formula at this point like this:


After the multiplication takes place, we have a single array like this:


Now you can see how the filter works. The values not created by formulas are "zeroed out". With just one array to process, SUMPRODUCT sums the array and returns a final result of 5950.

Not formulas

To sum values not generated by a formula, you can add the NOT function like this:


This is the formula in cell F7.  Here, the NOT function reverses the TRUE FALSE results returned by ISFORMULA function:


This causes the formula-created values to be zeroed out:


The final result from this formula is 9243.

Dave Bruns

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