How to round date differences to specific times?

Hi, I would like to calculate the halfway point between two date-time entries, but then I want as a result a time occurring between 8:00 and 20:00. So if the halfway point is outside this timeframe and before 2:00, it would round down to 20:00 the day before, after 2:00, it would round up to 8:00. How would I do this?

Thanks in advance for your help!

Screenshot 2020-11-25 120446.png

What about case "after 20:00" - should it round down to 20:00 current day ?

Yes, sorry, anything after 20:00 on same day would also round to 20:00


while waiting for a response to my comment, see the formula in column I of following sample file:

Formula in column I reads (formatted here for better readability of the 4 conditions used)

=IFS(       MOD(($B2+$C2)/2;1)<2/24                         ;INT(($B2+$C2)/2)-4/24; 
            MOD(($B2+$C2)/2;1)>20/24                        ;INT(($B2+$C2)/2)+20/24;
              1                                             ;($B2+$C2)/2)


  • Columns D through H are not required for the formula to work (only column B and C are used). I left em for the sake of understanding, how the formula works and for breakdown/testing purposes.
  • If have implemented a condition, which sets >20:00 to 20:00 (round down).
  • Rounding to full hours is in column J

Hope that helps.

Awesome! This is exactly what I wanted to calculate. Thank you so much!