112 Powerpoint | How to calculate slide duration?

Go under Slide Show tab and to Set Up section. Choose the box “Use
Rehearsed Timings” and click on “Rehearse Timings”. Now you can
tailor your presentation timings to your needs. You can see the
seconds pass and after the determined time you need has elapsed,
press on either “Next”, which is the first button in the menu and
takes you to next slide or “Pause” if you want to pause the timing
rehearsal or “Repeat”, which would restart the rehearsal. - Office
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