Subtraction for DateTime data type

[Aditya_Vinayak_]

I have a field by the name of check-in date & check-out date & Number of days.

In the Number of days I have put the below formula - TOTALHOURS([Check-Out Date]-[Check-In Date])/24.

But irrespective of the number of hours, I want only the difference in date to be calculated. Also, the initial value i want it to be set as 1 & not 0

[AleksiAlkio]

Are your column types Date or DateTime?

[Aditya_Vinayak_]

Check-In Date: DateTime
Check-Out Date: DateTime 

[AleksiAlkio · Accepted solution]

You need to convert your DateTime values to Dates. You can do that for example.. 

TOTALHOURS(DATE([Check-Out Date])-DATE([Check-In Date]))/24