And still, El Comandante’s listenership may have called itself lucky, because PowerPoint was only launched officially in May 1990. By extrapolating the slideware generating habits of some of my colleagues at work, I estimate that El Caballo’s oration might have been good for, say, 750 slides. As some sources claim that you need at least one hour of preparation time for each minute of presentation (which IMHO sounds a bit overdone,) this would have taken El Jefe Maximo a mere 430 hours (or almost 54 working days) of crafting. Maybe in Cuba, time isn’t (or wasn’t) money at all?
Your audience may be spending valuable time and money to attend a presentation too. Don’t waste it. No single presentation should take longer than necessary.
So, how long should the ideal slideshow take? There’s actually a very simple prescription for that, formulated by author and Canva evangelist Guy Kawasaki (about whom I have already written in my “Four storytellers about storytelling” post,) who called it the “The 10/20/30 Rule of PowerPoint”:
A PowerPoint presentation should have ten slides, last no more than twenty minutes, and contain no font smaller than thirty points.
And if the time slot that has been reserved for you happens to be longer or shorter than these 20 minutes, here’s another easy-to-use formula for calculating the number of visuals you can afford:
Always begin by deducting 1/5th from your speaking time, and reserve it for questions and answers. Then — assuming that the average presenter spends between 2 and 3 minutes per slide — divide the remaining minutes by 2 and by 3. The results of this simple calculation will give you an upper and lower limit for the number of visuals you can comfortably run through.