10/20/30 rule: what it means and other rules for good slides

The 10/20/30 rule sounds like a restriction, but in practice it's a way to force yourself to figure out what you actually want to say. Ten slides, twenty minutes, large type — and only the essentials are left on the screen. Here's where each number comes from, where the rule works, where it doesn't, and which other slide rules are worth knowing.

Where the rule comes from

The rule comes from Guy Kawasaki, a venture capitalist and former chief evangelist of Apple. He published it on his blog on December 30, 2005: The 10/20/30 Rule of PowerPoint. The trigger was the hundreds of startup pitches he sat through: long, packed with text and read straight off the slides.

The rule itself is short: a presentation has ten slides, lasts no more than twenty minutes and uses no font smaller than thirty points. Kawasaki adds that it isn't only for investors: it fits any presentation that should end in an agreement — a sale, a partnership, a funding round.

10 slides

Kawasaki's reasoning is simple: people can't take in more than about ten ideas in one meeting. And if you need more than ten slides to explain your business, he says, you probably don't have a business yet.

For a pitch he lists ten topics: the problem, your solution, the business model, the technology that makes it possible, marketing and sales, competition, the team, projections and milestones, current status and timeline, and a summary with a call to action. We cover this structure in detail in the guide on how to make a pitch deck.

For any other topic the ten works the same way: write down the ideas your audience should walk away with. If there are more than ten, some of them are details, and details belong in an appendix or a document you share after the meeting.

20 minutes

Meetings are usually booked for an hour. But some of that time goes to setting up the screen, someone arrives late, someone leaves early. Kawasaki recommends fitting your talk into twenty minutes so the remaining forty can go to discussion — that's where agreements actually happen.

In practice this means rehearsing out loud with a timer. If you run over, cut ideas, not speaking speed. Prepare answers to the questions you know will come; you can keep them on backup slides after the closing one.

30 points

Small type almost always means a lot of text, and a lot of text tempts the presenter to read it. The audience reads faster than you speak, gets ahead of you, and you fall out of sync. Kawasaki sees two reasons for small fonts: the presenter doesn't know the material well enough, or believes more text is more convincing.

Thirty points force you to keep only the main point on the slide and explain the rest with your voice. If that number feels too dogmatic, Kawasaki offers a fallback: take the age of the oldest person in the audience and divide it by two.

For reference: the standard widescreen PowerPoint slide is 13.33 × 7.5 inches, which is 540 points tall. Letters at 30 points take up about one eighteenth of that height, so not much text fits on such a slide.

When the rule doesn't work

• The presentation is read without you. A report or a proposal sent as a link has to explain itself: more text per slide and smaller type than on stage. What matters more is that each slide carries one idea — see our guide to report presentation structure.
• A lesson or a lecture. A class lasts longer than twenty minutes and has more slides. Attention comes from switching activities — explanation, example, question — rather than from a slide limit. See the guide on lesson presentations.
• A talk made of images. A conference talk can have forty slides if each one holds a single photo or a single phrase. The limit there is time, not the slide count.
• Complex data. Tables and methodology don't live well on slides. In his essay “The Cognitive Style of PowerPoint” (2003), Edward Tufte argued that the slide format chops reasoning into bullet points and gets in the way of serious analysis (edwardtufte.com). For the details, a document handed out after the talk works better.

Other rules for good slides

No more than six words on a slide. In “Really Bad PowerPoint” (first an ebook, on his blog since 2007) Seth Godin goes even further: six words, no exceptions. The core of his approach is that slides reinforce what you say instead of repeating it. He suggests putting the details in a separate document and handing it out after the talk, not before — otherwise people read it instead of listening.

Assertion and evidence. For scientific and technical talks, Michael Alley of Penn State proposes the assertion–evidence approach: the slide headline isn't a topic but a complete message in one sentence, and below it comes visual evidence — an image, a chart or a diagram — instead of a bullet list. “Results” tells the audience nothing; “The new alloy carries twice the load” does.

One idea per slide. This is what all the rules share: if a slide holds two ideas, the audience remembers one, and not necessarily the right one.

How to do it in JamPres

The first creation step has “Length”: leave it on “Auto” or set exactly 10 slides with the “Fewer slides” and “More slides” buttons. You can adjust the outline before building: remove a point, rewrite it, drag points into a different order. For a pitch, choose “Pitch” in “What it's for”: this purpose plans one idea per slide, in large type.

The template sets the font size. When there's more text than a slide's space holds, the type shrinks — treat that as a signal to cut. The editor's “AI” tab has “Shorten”: the model trims the slide's text, and a single undo brings it back. Put what you'll say out loud into “Speaker notes” in the slide panel — they're not included in the publication.

Twenty minutes is checked in a rehearsal: “Present” on the presentation page opens the slides full screen. And if you send the presentation as a link, “Analytics” shows the average view and how far people read — that's from the Base plan.