How to figure out the optimal interval for a time lapse movie?

Question

What would be the optimum shooting time interval if I wanted to make a time lapse movie over a period of ~7 hours? The setting is indoors (think office space). I don't want it to be blazingly fast-- I suppose the goal of the shoot is to "summarize" the place and just show what a day is like in approximately 2-3 minutes.

Answer 1

Assuming a 2 minute video for 7 hrs, at 24fps, 2 × 24 × 60 = 2880 frames in total. So in 7 hours you need to take around 2880 frames, 7 × 60 × 60 ÷ 2880 = 8.75 — you need to take pic every 8.75 seconds. (Some people shoot at more or less fps to create varied effects.)

Answer 2

This is just "formularising" @user9832 's answer.
If you like this, upvote his / her answer.
user9832 is welcome to copy this or use an amended form if desired

Time between photos

• = (Seconds_in_time_recorded) / (seconds of watching time x frames_per_second)

eg 7 hours 30m in day.
3mins 30s display time
30 frames per second display rate.

Seconds in day = 7 x 3600 + 30 x 60 = 27,000
Seconds in playback = 3 x 60 + 30 = 210.
fps = 30

Time between photos = 27000 / (210 x 30) = 4.286s =~ 4 or 5 seconds