Share via

When will support for Date type input parameters be added to task pane add-in custom functions for Excel?

Brooke Mackey 0 Reputation points
2025-05-29T15:57:52.3+00:00

I am developing an Office Excel Task Pane Add-in with custom functions and, as of right now, there is no support for Date type input parameters other than workarounds using strings or Excel date serial numbers. This seems like a pretty basic and necessary data type to include in custom functions. When will this be added?

Office Development
Office Development
Office: A suite of Microsoft productivity software that supports common business tasks, including word processing, email, presentations, and data management and analysis.Development: The process of researching, productizing, and refining new or existing technologies.
4,366 questions
0 comments

1 answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. Austin-H 2,775 Reputation points Microsoft External Staff Moderator
    2025-05-30T03:00:11.02+00:00

    Hi @Brooke Mackey ,

    Thank you for your inquiry regarding support for Date type input parameters in Excel custom functions. 

    From what I’ve found through available documentation and current guidance, Excel custom functions in Office Add-ins do not support Date type input parameters directly. This is a known limitation, and while it has been raised by the developer community, there is currently no official timeline for when native support will be introduced. 

    As a workaround, developers typically pass date values as either Excel serial numbers (e.g., 44561 for May 30, 2025) or as ISO 8601 date strings (e.g., "2025-05-30"). These values can then be parsed and handled within the function logic as needed. 

    For more information on how to implement and manage custom functions, Microsoft provides detailed documentation that may be helpful. You can refer to the following resources: 

    We encourage you to regularly monitor the following official channels for updates on upcoming features and developer advancements: 

    Your feedback is important and helps shape future product improvements. We encourage you to share your use cases and vote on existing ideas via the Microsoft Feedback Portal forum. 

    We hope this explanation clarifies the current behavior and provides helpful resources for tracking future updates and exploring Excel Add-in capabilities in more depth. Please feel free to reach out if you have any further questions. 

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".  

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Your answer

Answers can be marked as Accepted Answers by the question author, which helps users to know the answer solved the author's problem.