Using formulas in date fields which reference another field

edited 12/09/19 in Formulas and Functions

I'm trying to enter a formula in a date field which is 10 days earlier than the date in another field. I read that I can perform calculations on date fields ( and reference another cell in the formula (

My formula is

=[Start Date]42-10

because I want the date that is 10 days earlier than the cell in row 42 of the "Start Date" column.

However, when I enter this formula in the cell and hit Enter, all I see is the formula itself. See attached screenshot. What am I doing wrong?

Screen Shot 2019-10-22 at 2.30.23 PM.png



  • Frank Falco
    Frank Falco ✭✭✭✭✭✭
    edited 10/23/19

    If the date column is assigned to either the start or end date columns and you have dependencies enabled in your project settings you cannot have a formula on it. These fields are calculated my SmartSheet based on the dependencies.

    The project settings are accessible in the Gantt View via the cog (settings) icon under the Share button.

    ✅Did my post help answer your question or solve your problem? Please help the Community by marking it as the accepted answer/helpful. It will make it easier for others to find a solution or help to answer!

  • Paul Newcome
    Paul Newcome ✭✭✭✭✭✭

    Frank is correct. It seems as if you have your dependencies enabled and are using that column as one of your project columns. You have a few options...


    1. Disable dependencies in the Project Settings.

    2. Create another column for the calculated dates.

    3. Select a different column in your Project Settings.

    4. Add lag/lead time if establishing predecessors.

  • Thank you, Frank and Paul!

  • Paul Newcome
    Paul Newcome ✭✭✭✭✭✭

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