Need help with a formula to calculate end time based on start time and duration!

[Jennifer_Greybe]

Hi Airtable community! I am planning a conference that has multiple sessions per day over multiple days, and as we tweak the schedule, I don’t want to have to manually compute the session start/end times. The duration of each session is pretty set in stone.

I need a formula that will calculate the END TIME of an event based on the START TIME and DURATION of that event. For example, I have a session starting on 10/19/20 at 12:00pm. It lasts 20 minutes. It ends on 10/19/20 at 12:20pm. But that might change, and I’d like to be able to update either the start time or duration and not have to manually update the end time.

Any assistance here would be much appreciated!

Thank you,
Jennifer

[ScottWorld]

Welcome to the community, @Jennifer_Greyber!

This is very simple.

Create a “Duration” field and set it to the “Duration” field type.

Then, create an “End Time” field, which is a “formula” field type.

This is the formula to use:

DATEADD({Start Time}, {Duration}, 'minutes')

Hope this helps! If this answers your question, could you please mark this comment as the solution to your question? This will help other people who have a similar question. :slightly_smiling_face:

[Jennifer_Greybe · Accepted solution]

Hi ScottWorld! Thanks for your quick answer! Yes, that answers the question I asked. I do have a follow up question as well. Is there a way to create a formula that automatically updates the times (either start or end) if I change one or the other? In other words, if I tweak the schedule in some way, I’d like for all the times for that one day to update automatically instead of having to manually adjust each one. Does that make sense?

Thanks,
Jennifer

[ScottWorld]

Glad I could help! :slightly_smiling_face:

No, you wouldn’t be able to do that with formula fields, because formula fields can’t have their values edited. So that situation would be more of a challenge… the only way to do that would be to switch back to a date field (instead of a formula field), and then create some sort of automation to automate the process somehow. Perhaps by using Airtable’s built-in automations, or maybe a custom JavaScript, or perhaps with Integromat or Zapier.

[Jennifer_Greybe]

Thank you! Automations sound interesting but probably not necessary at this point for our event.

Jennifer