we need more details on what you trying to do, what error do you get, what environment you work on, is it for form or workflow, etc, etc...

This thread may help.  https://community.nintex.com/message/56376-re-date-comparison-in-wf

I'm using SharePoint Nintex form. I have two columns in the form. Meeting_Start captures the date and time for the beginning of the Meeting. Meeting_End captures the date and time the meeting ends. I'm using a validation control to compare date and time to make sure that the user doesn't select a start date and time that is great than the end date and time. Also, the reverse for End_Meeting. The control only compares the dates and throw an error when it sees the same date. For example: 5/12/2017 12 pm is start and 5/12/2017 1pm is end. I'm getting the error message I created because it's only comparing dates and not date and time.

I'm using SharePoint Nintex form. I have two columns in the form. Meeting_Start captures the date and time for the beginning of the Meeting. Meeting_End captures the date and time the meeting ends. I'm using a validation control to compare date and time to make sure that the user doesn't select a start date and time that is great than the end date and time. Also, the reverse for End_Meeting. The control only compares the dates and throw an error when it sees the same date. For example: 5/12/2017 12 pm is start and 5/12/2017 1pm is end. I'm getting the error message I created because it's only comparing dates and not date and time.

Check out the Date and Time Format Strings - Quick Reference Guide article from Andrew Glasser and see if this helps with the date formats.

hwo do you compare it?

see following how should it work  

So you can't do this? My Validation Rule is comparing the two controls by time.

This works. Thanks!

Awesome, glad we were able to help. Please mark the answer correct as to benefit others with the same question. Happy Nintexing!

Hello ,

I am new for Nintex and trying to do

Nintex Forms 2013 , I want to validate a time field that's is a single line of text field so
 user enter the start time prior to the end time . The time formatted regex for validation (24-hour clock format  ). How can i accoplish this. 

Thank you very much for  your assistance.

Sosena