StartDate + TaskDays = DueDate

Question

I need help with SharePoint Workflow, I want to add dates based on lookup from a different column.
For example -

Column A (StartDate) + Column B (TaskDays, numbers) = Column C (DueDate)

Reason I want to use DueDate its easy to use the same for Task Timelines. Other wise I am able to create Column D with Calculated field, i.e. =[StartDate+2]

Thank you for your help in advance!

Answer 1

to do this using SharePoint designer workflow,

1. in Action button on the ribbon , add add time to date action
2. in the days property , add your Task days field (number type).
3. in to date add your start date (date type).
4. the result will be set in the output variable as on the below screens.
5. back to Actions again and add Set field in current item action
6. set the due date field with the output date variable.

Answer 2

You can make it very easy and quickly using Javascript CSOM. First reflect if you really need a column just to add the days. If you don't just put business rules inside a Javascript function. Use a common input field (a date field from your Javascript Framework). Do it in client before submitting. Another approach is just to do it using a Workflow that format and sum the dates. You can save hundreds work hours using SharePoint Workflows. The last option is using a calculated column with an editorial workflow to do the math.