Expiration Date From a Start Date
This calculated column uses a SharePoint formula to set an expiration date a fixed number of days after a start date. Because it lives in a calculated column, SharePoint fills the value in for every item automatically - no custom development and nothing for your users to type.
How It Works
- What it does: Adds a fixed number of days (90 here) to a Start Date to set an expiration date.
- What you get: A date – a Start Date of 1/1 shows 4/1.
- If a value is missing: If Start Date is blank, the column shows a blank or an error instead of a date.
Common Use Cases
- Certificate or license validity from an issue date
- Warranty windows from a purchase date
- Trial or subscription end dates from a start date
- Follow-up deadlines a set number of days after kickoff
Details
- Formula Type: Calculated Column
- Formula Category: Dates & Time
Required Columns
| Display name | Column type |
|---|---|
| Start Date | Date and Time |
| Expiration Date From a Start Date | Calculated |
Prerequisites
- Create the column the formula reads: Start Date
- Add or edit a few items so there is data for the formula to work with
How to Apply the Formula
- Add a column, choose More…, then select Calculated (calculation based on other columns)
- Set the data type returned from this formula to Date and Time
- Paste the formula below into the Formula box
- Click OK to create the column
Formula
=[Start Date]+90Common Questions About Expiration Date From a Start Date Formula
What does this formula do?
Expiry based on a start/effective date. It lives in a calculated column, so SharePoint fills the value in automatically for every item.
Which columns do I need to set this up?
You need: Start Date (Date and Time). The formula reads these to produce its result.
Can I change the formula for my own columns?
Yes. Swap the column names in brackets for your own, and adjust any numbers or text.
If LookBook 365 is code-free and out-of-the-box, why does this example use a formula?
A SharePoint formula is native, declarative configuration, not custom development. It only works with the item’s own fields and simple logic – it cannot run scripts, reach external services, or change other data, and nothing is deployed to your tenant. It keeps working through Microsoft updates. If you would rather not set this up yourself, this is exactly the kind of thing I configure for clients.
Expiration Date From a Start Date Formula Example