After you've opened the presentation you want to rehearse, open the Slide Show menu and select Rehearse Timings.
Rehearse your slide show, clicking the Next button on the Rehearsal toolbar to move through each of the slides as you would perform them.
When you finish rehearsing the slide show, PowerPoint asks whether you want to record your slide times. If so, click Yes.
PowerPoint displays these times in Slide Sorter view.
INTRODUCTION
When people create presentations, they usually have a specific time limit they need to stick to. Instead of using your watch and trying to time the show yourself, why not let PowerPoint do the work for you? If you need to stop and make some notes, you can pause the time recorder. If you get off to a bad start or need to repeat the rehearsal, you can click the Repeat button. When you get to the end of the slide show, PowerPoint asks whether you want to record the slide times; if you do, Slide Sorter view shows recorded times with each slide.
TIP
Canceling the Rehearsal
You can click the Close (x) button on the Rehearsal toolbar to cancel a rehearsal and resume working in the presentation.
