While the answer can vary from project to project, here are some thoughts from DeckRobot to guide you.
A quick search of the Internet will tell you that the minimum size is from 18 to 36 pt. Admit it - that's quite a range! Figuring that out is more complicated. Dave Paradi created a formula for font size based on the standard for US road signs, which allows for average eyesight to see what’s written. Here are the tables that he created based on this purpose.
4:3 ratio screen distance for viewing font size
16:9 ratio screen distance for viewing font size
But let's be real. How often do we know these variables or have the time to measure them? Without knowing the exact size and ratio of the screen or the layout of the court/mediation location you easily can mess up your presentation with the wrong size choice.
Always consider your audience. Try to visit the place where you will be presenting beforehand. Check the space in which you will be presenting your deck. If presenting in person, how deep is the room, and how far back might the farthest person be? Will your screen be viewed on a computer or a smartphone potentially? Take the time to view your presentation from the farthest seats. While 20/20 vision is perfect, not everyone in your audience will be able to see what’s written on your slides. A good place to start is crafting your slides so that anyone can see each word clearly.
If you want your audience to be able to see what you have on the slide, there needs to be a lot of contrast between the text color and the background color. Dark background with light text is the best option. Some prefer a light background and dark letters, which will also work well - which you choose will depend on personal preference. Don’t think that just because the text looks fine on your computer screen that it will look fine when projected. Most projectors make colors duller than they appear on a screen, and you should check how your colors look when projected to make sure there is still enough contrast.
Visuals VS Text
The latest survey confirms that audiences are more fed up than ever with the overload of text on slides (see the latest survey results here). Instead of using slides that only contain text, use visuals such as graphs, diagrams, photos and media clips to engage the audience.
What should you be thinking of after you select the correct font size for your slides?
What font-face should you use? Read our article about “8 Best Fonts to Use for PowerPoint Presentations in 2021”
Make sure that the message of your presentation is clear for your audience.
Why you should select visuals instead of slides full of text or spreadsheets? Read our article about “Why Presentation Visuals Are So Important”
Simply stated, if you are wondering if the text size is too small—it probably is. But more importantly, keep the text on each slide to a minimum! Find a way to balance the weight of the other visual elements of your slide to increase the text size. Better yet, find a way to visually show what you are talking about instead of relying on text.