Generating ready dates

Does anyone know if it is possible to create things (possibly events) that take a set amount of time (ie 30 days) so that when the person starts that thing on today’s date it automatically displays the due date for 30 days from today?

Hopefully I explained that well enough.

I want people to select a job from a dropdown menu and select what day they start the job. Then I want an automatically generated due date for that job based on how many days that job is set to take.

Is this possible?

Yes this can be easily done. Try a bit around with the +(days)…