DateKeys are essential for relative time measures. In “manage relationships” you tie the ‘DateKey'[Date] to a date field in each of your data sources. Giles Walker shared an excellent solution for a robust DateKey that includes measurements and calculations you’re sure to find useful. Here’s that same solution I’ve modified and expanded to be as useful as possible.


Note: I previously shared how to do this in SharePoint Designer. The following method utilizing Flow is better, and does not use loops/pauses.

It’s well-known that SharePoint calculated columns don’t permit [Today] to be used as a formula for a calculated date column. And the “default to today’s date” setting only works upon creation, and doesn’t update daily. But we can create a standard date column and have Microsoft Flow automatically update it daily for us, therefore allowing us to effortlessly perform calculations against today’s date such as:

  • Age =(TodayDate-Birthday)/365
  • Years of Service =(TodayDate-StartDate)/365
  • Days Past Due =(TodayDate-DueDate)
  • Weeks until summer break =(SummerStart-TodayDate)/7

Here’s how to create your own, always accurate/updated, today column (see bottom of post for video):


This is a fairly simple solution that takes a date column, compares it to another date and gives you an answer in years (or days, or whatever you want). You’ll need to already have date columns to work with, and if comparing the date to today (years of age, membership, service, etc.) you’ll need a today column (hidden from the view above). This previous post will help you rig a “today” column that is always accurate without needing to update list items manually. Of course all of the following solutions work for any two dates (i.e. day span of vacation request), I’m just sharing specific examples that would involve “Today”.