> For the complete documentation index, see [llms.txt](https://kb.logicerp.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kb.logicerp.com/logic-erp-learning-hub-tutorials-and-best-practices/defining-custom-columns-in-reports-and-grids-with-expressions/dateadd-function.md).
# DateAdd() Function
**YouTube:** [How to Use the DateAdd() Function in Report Custom Columns?](https://www.youtube.com/watch?v=nV83ZdKfumU)
## How to Use the DateAdd() Function in Report Custom Columns?
In this tutorial, we will learn how to use the **`DateAdd`** function to perform **date arithmetic**—like adding months or days to an existing date, such as a bill date.
***
### Accessing the Expression Designer:
* Navigate to the **Reporting** section.
* Open the **Sales Register Detailed Report** or any **"Report".**
* Go to **Setup Column Attributes**.
* Here, you'll see a list of available columns that can be used to build expressions.
* Click on **"Add/Edit Expression Columns"** where you can write your expression using predefined functions.
* Before adding the expression to the report, go to **Other Settings**.
* Ensure the **Script Editor** is set to **VBScript**.
* Click **Save**.
* *Note: VBScript is the default for new configurations but always verify this setting.*
### Writing Your First Expression
* Every expression must start with the script header: **'#@LSCRIPT**
* Click the (+) Plus icon to create a new expression.
* Fill in the required fields:
* **Expression Name** – A unique name for your expression.
* **Expression Type** – Choose either **Text** or **Numeric** depending on the expected output.
### Creating a Simple DateAdd() Expression
* Double-click the new expression name to insert it into the script editor.
* Define the expression using the syntax:
* **Expression Name** = DATEADD("M",CDATE(BILL\_DATE),4)
* `"M"` → adds months.
* `CDate(BILL_DATE)` → converts the bill date into a valid date format.
* `4` → number of months to add.
* Save the expression once defined.
* Scroll down and **check the box** beside the expression name to enable it.
* Save and proceed to check the effect.
* **Refresh the report** to view the final result.
***
### Output:
* If your bill date is `01/06/2025`, the `"M"` interval will show: `01/07/2025`.
* The `"D"` interval with 10 days will show: `11/06/2025`.
This function is useful for calculating **due dates**, **next follow-up dates**, **expiry dates**, or **any schedule based on the transaction date**.
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