The standard formula that isn’t helpful because it treats weekend days like workdays is:

IF({Start},DATEADD({Start},{Days},'days'))

You’re pretty close, you actually need WORKDAY() instead of WORKDAY_DIFF()

So your formula should be WORKDAY({Start},{Days})

Hi everyone – I’m a total beginner, looking for something similar, but in reverse. I have a DueDate field. Can I generate a StartDate field with a formula that subtracts 14 workdays from the due date? Can the StartDate field be in a date format, so I can see the results in a calendar view? Thanks so much for your help!

Use a negative number: WORKDAY({DueDate},-14). And yes, you can format the result as a date to be used in the calendar.

THANK YOU so much! This is awesome.

What would the formula be to calculate the date based on days not workdays? many thanks!

^ that’s the “normal” date calculator function. You can replace the field reference {Days} in that example with a static number (i.e. 14). All date generation formulas in Airtable accept negative numbers.

Really hoping you all can help me figure out what I’m doing wrong!

I am trying to use a Rollup to calculate my estimated days (summing the estimated times for the tasks that are associated with that project), and referring to THAT in my due-date formula.

I’m using columns which are called:


– Kickoff date


– Time estimate Rollup (which is pulling estimated times from my Tasks table)


– Calc. Due Date

In that Calc. Due Date columns, I’m using the formula: IF({Kickoff date},WORKDAY({Kickoff date},{Time estimate Rollup}, ‘days’))

When I save, I get an Error in each row that has rolled up dates. In records that don’t have rolled up dates, the formula seems to work of course! Pic attached.

What am I doing wrong?

You’re confusing the format for WORKDAY() with the one for DATEADD(). WORKDAY() only requires two arguments, and if there is a third argument it would be a list of holidays to exclude from the calculation. Notice how all the examples above are written. Get rid of the , 'days' bit from your formula.