**Used for: **calculating the sum of a field that contains a list of numbers.

**Used in:** "THEN"-statements and "ELSE"-statements.

The "calculate sum" rule is used to calculate the sum of a list of numbers. An example use case is when you have a list of stock numbers for every size of a product. Using the "calculate sum" rule you could easily calculate the total stock amount for that product, which would look like shown below.

The output of this rule would look like this: