What precisely is the 10/20/30 rule of PowerPoint?
The 10/20/30 PowerPoint rule is a pretty simple idea. You should always use ten slides max, talk for no more than twenty minutes, and always use fonts larger than 30-point. Guy Kawasaki dreamed up the concept. The aim being to provide clear, informative presentations.
Kawasaki believed that ten concepts were the limit for most audiences and that you should limit the amount of text on each slide, summarizing rather than going into too much detail. You can give more information and data verbally but minimize the text and detail on the actual slides.
You've got ten key points, but you want to limit the time the presentation takes to just twenty minutes. That makes it simpler to plan the structure of your talk. You're aiming for two minutes per slide max. Even though you'll generally be given more time for your presentation, limiting the structure to twenty minutes allows for questions and discussion - and in case you run into technical issues during the talk.
Slides with smaller fonts can be really hard to read, especially if you're at the back of a room. Kawasaki reckons that if you keep the information on slides minimal, 30-point is achievable. That serves the purpose of encouraging the audience to concentrate on what you're speaking about rather than struggling to read.
Each element of the 10/20/30 rule promotes the other. The ten limit encourages you to keep things to the important points. The 20 limit means you're not going to stray from the core subject verbally. The 30 rule keeps all the points on each slide relevant and key to the overall concept.