I'm trying to add validation to a text column in an SPO list so that entered data only contains values from 00:00 to 23:59. I referred this article for a validation code which works fine. But it does not allow blank values. How can I accomplish this?

  • From the link you provided, which formula worked for you (which user's answer worked)? I will extend the same formula & provide you updated formula for this question. Jul 28 at 11:35

1 Answer 1


If you want to allow blank values in column validation, use formula like:

=IF(ISBLANK([Start Time]), TRUE, <current formula which worked for you goes here>)

For Example:

=IF(ISBLANK([Start Time]), TRUE, (LEN([Start Time])=5)+(MID([Start Time],3,1)=":")+(CODE(MID([Start Time],1,1))>47)+(CODE(MID([Start Time],1,1))<51)+(CODE(MID([Start Time],2,1))>47)+(CODE(MID([Start Time],2,1))<58)+(CODE(MID([Start Time],4,1))>47)+(CODE(MID([Start Time],4,1))<54)+(CODE(MID([Start Time],5,1))>47)+(CODE(MID([Start Time],5,1))<58)+IF(CODE(MID([Start Time],1,1))=50, (IF(CODE(MID([Start Time],2,1))>51, 0, 1)), 1)=11)

Update from comments:

I just tried this in my SharePoint site & it allows blank value from list forms as well:

enter image description here

  • Hi @Ganesh, This works fine when I'm editing or adding new item via grid view. But when I add/ edit an item using new/edit form, it does not allow blank values. Can you please check this scenario?
    – Robin Roy
  • I just tried this in my SharePoint site & it allows blank value from list forms as well. See screenshot in my updated answer. yesterday

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