Using GoCanvas to automate calculations and summarizing values is a great tool to save time and reduce errors. 

Sum Calculation

GoCanvas forms can do the math for you. The Calculation field in the Builder has two functions: automatically compute simple mathematical functions as well as summarize all instances of a number or calculation field in a Loop Screen or Table.

Below, we will build upon the concepts covered in the Help Center article, "Calculating Values and Constants," where the calculations were built on a screen. In order to use the Sum Calculation Type, the fields must be located on a repeating screen type, i.e. Tables, Loops Screens, or Lists.

Summarize 

Sum Calculation fields are used exclusively to summarize Number or Calculation fields located in a repeating screens types. Regardless of the amount of rows, this field will add every value together to give a total on a later screen. This solution requires a previously established List, Loop Screen, or Table with a number or calculation field as well as a separate simple screen with a calculation field.

1. Find or create a repeating screen type with a number or calculation field. You can use the example in the article, "Calculating Values and Constants" and simply convert the screen to a Table or Loop Screen.
2. On a separate simple screen, add a Calculation field using your preferred method.
3. Label this something descriptive, like "Product Total" based on the example in the previous article, linked above.
4. Select the field or the orange triangle beside the field to open Field Settings.
5. Toggle the Calculation Type to Sum.

   

6. Expand the drop down for Sum Field and select the "Subtotal" field from the repeating screen containing the initial product information.
7. Expand the Format drop down and select Currency.

   

The Product Total field will automatically summarize every row from the repeating screen, regardless of how many rows, once there are values captured in the submission. 

Save and Test your calculations to be sure they work as expected, either from within the Builder or Publish to test on mobile.

Calculations on Mobile

Here is how the example above looks on mobile.