I’m building a timeline and would like to create a formula so I don’t have to enter start and end dates. The formula would calculate the end date based on the start date and a “duration” field. The number of days varies depending on the task.
Take a look at the scheduling framework I recently published in Airtable Universe. (The original announcement, which goes into some detail, can be found here.) I suspect at first glance it may appear more involved than you want, but I think you’ll find the complexity is necessary to deal with the inevitable exceptions that may arise — shifting end dates off of weekends and holidays, for instance. You should be able to duplicate the example base provided, delete the sample records, and start to use it immediately.
Briefly, to use it you would define task types in the
[Templates] table. (For your purposes, you wouldn’t need to define subtasks — which would also greatly simplify creating task instances.) Once the task types are configured as to duration, weekday/workday, and previous/following workday, when applicable, you would then create instances of tasks in the scheduling table, assign them a task type, and everything else would be calculated automatically. (If you want to be able to use a calendar view to shift multi-day tasks using drag-and-drop, you’ll have to perform a manual step to create a schedulable date range [Airtable does not allow you to drag-and-drop a date range with a calculated end date; the framework provides a workaround] — but that’s a 2-click/2-keystroke action.)
[Documentation] table of the published base contains a users guide as a PDF attachment that offers a step-by-step explanation of the routines.
Feel free to message me here with questions…