The DATEADD() formula I think will do the trick here. I’m a little unclear how, or if, the days bred/date checked columns should affect the Estimated Day of Arrival. But for a simple Start Day + Average Gestation time = ETA formula, you could use

DATEADD({Start Date}, {Gestation}, 'days')

You can read more at the documentation if you would like:

Formula field reference

For an overview of formula fields, please refer to the Guide to Formula, Lookup, Count, and Rollup fields.

Formulas may involve functions, numeric operations, logical operations, and text operation...

The DATEADD() formula I think will do the trick here. I’m a little unclear how, or if, the days bred/date checked columns should affect the Estimated Day of Arrival. But for a simple Start Day + Average Gestation time = ETA formula, you could use

DATEADD({Start Date}, {Gestation}, 'days')

You can read more at the documentation if you would like:

Formula field reference

For an overview of formula fields, please refer to the Guide to Formula, Lookup, Count, and Rollup fields.

Formulas may involve functions, numeric operations, logical operations, and text operation...

Great! I was able to figure it out easily by tweaking the formula you provided. One more question. Is there a way to remove the time on that? It’s providing me with a day and time (12:00am) we don’t really need the time.

Thanks again!

Yes, if you go into the “Formatting” tab (right next to where you edit the formula), you’ll notice there’s an “Include a time field” option. If you’d like, you can also change how the date displays here as well.