+1 I have the exact same issue. I feel like I am so close, just missing this key puzzle piece.
Calling in the cavalary!
Each of you have had thoughtful answers to the timezone problem in other threads.
Our app involves users submitting their availability to meet. We want other users to view this availability from their own local time, hence having users select local time zones and passing everything through a standardized UTC date/time is essential.
In our app we will have users select their preferred country time zone and the date/time picker. Then I have a UTC Offset column corresponding to the time zone. The offset is in seconds, and can also be translated to hours using a Math function: SECONDS / 360.
The question is how to apply the offset (in either seconds or hours) to the submitted local date/time and create a translated UTC date/time.
I tried to use the Math function to add/subtract the offset to the local date/time (LOCAL + OFFSET), but it only shows the OFFSET number.
BTW, these were handy CSV data files for grabbing UTC offsets for standard time zones: