I miss 2 closing parentheses, from the DATETIME_DIFF. Also the second {Purchase Date} has no opening bracket.

Didn’t work, but I found an alternate solution. It accepted my Datetime_diff if it were the 3rd item in the if statement, but not the second one.

I don’t understand your last message, but I’ve created a simpler formula that works:

IF(Sale, DATETIME_DIFF( Sale, Purchase,'d'),DATETIME_DIFF( TODAY(),Purchase,'d')).

You can see my table: https://airtable.com/shrM7rGbN4msFSGPT

• You don’t need to wrap the DATETIME_DIFF function



• You don’t need a field for Today, as you have TODAY() function



• You don’t need to make = ""with the Sale Date



• Recommendation: field names with just one word, so you don’t need the {}:
  
  
  
  
  
  • Just Sale, as it’s a Date field
  
  
  
  • Join words as SaleDate
    
    
  
  
  
  • Separate words with an underscore: Sale_Date.
  
  
  
  
  
  

Thank you for the help!