The 10/20/30 rule and when to break it

Guy Kawasaki's 10/20/30 rule has been a useful default for pitch decks for two decades. Ten slides. Twenty minutes. Thirty-point font. The rule has earned its longevity because it works for the situation it was designed for: a venture pitch where the investor has limited attention and limited patience.

But the rule does not always work, and the situations where it should be broken are worth naming.

When 10/20/30 works

The rule was built for a specific scenario: a founder pitching for venture capital in a 30-minute meeting where the deck is the primary artefact and the meeting is a single use.

In that scenario, the rule produces a deck that holds attention without overwhelming, communicates the essentials in a tight time window, and leaves room for the conversation that actually closes the round.

The rule still works for: investor pitches at seed and Series A, partner conversations early in a sales cycle, board updates where time is tight, and external speaking slots where the speaker has not earned the right to a longer slot.

When to break the 10-slide rule

Some senior contexts genuinely need more than ten slides.

A board strategy deck for an annual review usually needs 25 to 40 slides. The audience expects depth. The deck is read in advance and discussed in detail.

An executive committee technical review needs 15 to 25 slides. The technical detail is the work. Compressing it produces an unhelpful surface skim.

A conference keynote sometimes needs 30 to 60 slides, particularly when the talk is built around frequent slide changes that pace the narrative. The slides are punctuation, not chapters.

The discipline here is not slide count for its own sake. It is the question: what does this audience need to read or see in order to engage with the material?

When to break the 20-minute rule

The 20-minute rule was built for a specific kind of attention. Some contexts allow longer attention spans.

A board meeting where the deck is one of three agenda items can run 45 minutes. The audience has set aside the time and is engaged.

A workshop or training session can run 60 to 90 minutes per deck. The format is built for sustained attention.

A keynote at an industry conference can run 30 to 45 minutes. The audience has chosen to be there.

The trap is assuming the rule applies in every context. The fix is to read the room: how much attention is the audience prepared to give, and what depth does the material genuinely require?

When to break the 30-point font rule

The 30-point font rule was a reaction to decks crammed with text. Many investor pitches in the 1990s and 2000s used 12-point body text on every slide. The rule was a corrective.

But some deck types genuinely need smaller text. A data-heavy slide showing comparison tables. A regulatory slide listing specific framework requirements. A team slide listing 8 senior hires with one line each.

The discipline is to not use small text as a default, but to use it deliberately when the slide carries dense content that the audience genuinely needs to read.

A deck with three text-dense slides among 14 readable slides reads as a deliberate document. A deck with all 14 slides text-dense reads as a thicket.

What 10/20/30 was really getting at

The underlying point of the rule is the more important thing than the specific numbers. The point is: respect the audience's attention. Do not assume they will read 60 slides. Do not assume they have an hour. Do not assume they want to read 11-point text from across the room.

The numbers are a default. The respect for attention is the principle. The senior speakers who internalise the principle, rather than the numbers, build decks that work across more contexts than the strict rule allows.

The default that still works

For most senior speakers in most contexts, the default of "fewer slides than you think, less time than you would like, larger text than feels comfortable" is usually right. Slide counts in the 8 to 18 range, talk lengths in the 10 to 25 minute range, and minimum readable text from across the room.

The default works because most decks are over-built. Speakers who push toward a tighter default usually produce sharper decks. Breaking the rule is a senior move worth knowing how to do, but the default is usually the right starting point.