How to Check If a Date Falls Within 30 Days of an Array of Dates in Airtable

You have a column A that stores a single date. For example, the value could be 24-07-24.

Then you have another column B that is a lookup field and it returns an array of dates. This could be three or four dates coming from linked records.

The goal is to determine whether any of the dates in that array fall within a range of 30 days before or 30 days after the date in column A. If even one date falls in that window you want the result to be true. If none of the dates fall inside the window you want the result to be false.

Normally Airtable does not allow formulas to loop through arrays, so you cannot directly compare each date in the lookup field against the date in column A.

For this specific case there is a very clever technique that we can use to figure out if the dates falls inside the date range.

Turning the Lookup Into Two Rollups to Build the Date Range

The first thing you do is convert the lookup in column B into a rollup. Set the rollup to use Min(). This gives you the earliest date from the entire array.

Then duplicate this rollup and change the aggregation to Max(). This now gives you the latest date from the array.

At this point you have the earliest date and the latest date, which together represent the full range of all dates inside the lookup array.

Once you have these two rollup fields you can check whether the date in column A has any overlap with the thirty day window around those dates. If the window around A touches the earliest or the latest date it means at least one of the lookup dates is within thirty days before or after the date in A.

Here is the formula that performs this check:

IF(
  AND(
    DATEADD({Date A}, -30, "days") <= {Latest Date},
    DATEADD({Date A}, 30, "days") >= {Earliest Date}
  ),
  true,
  false
)

This formula expands the date in column A by thirty days in both directions and then checks whether this expanded range overlaps with the range created by the earliest and latest lookup dates. If the two ranges overlap the formula returns true. If they do not overlap it returns false.

This approach gives you a clean and accurate solution without needing scripts or automations, and it works inside Airtable’s standard formula and rollup fields.