If you’re asked to do a keynote speech, you might wonder, How long should it be? 15 minutes. An hour. Somewhere in between?

And the short answer is—it depends.

For professional keynote speakers, their average keynote speech ranges between 30 and 60 minutes in length, depending on the needs of the engagement. 

You might find some event planners ask for 60 minutes of your time, while others want to keep your presentations short and sweet. For example, TEDx limits its speakers to a maximum of 18 minutes. They believe 18 minutes is the sweet spot for an audience’s attention span.

While that’s great for TEDx, it doesn’t really allow a speaker to go into depth on a topic.

And that length doesn’t even include a Q&A portion, which many event planners ask for. A good Q&A after the keynote speech could add another 15-30 minutes to your talk.

So, what should you do as a keynote speaker?

Plan for the long talk.

It’s always easier to make a long talk short than a short talk long, so plan for the long talk.

Professional keynote speakers typically create keynotes that last 45 to 60 minutes. And then they can cut back their content and slides, depending on the length of the engagement.

For example, James Clear, author of the 20 million-copy-selling Atomic Habits, has 30-, 45-, and 60-minute versions of his talk on the science of habits, which he can deliver to any in-person or virtual audience.

Try the 10-20-30 rule.

You might also consider the advice of Guy Kawasaki, creator of the Remarkable People podcast, on how to do a presentation.

He suggests people follow the 10-20-30 rule, which breaks down like this:

10 slides. According to Kawasaki, “Ten is the optimal number of slides in a PowerPoint presentation because a normal human being cannot comprehend more than ten concepts in a meeting.”

20 minutes. Even though you may have an hour slot to speak, most presentations have technical problems, so plan on twenty minutes of presenting. This allows time to work out the audiovisual kinks and also leaves plenty of time for Q&A afterward.

30-point font. A bigger font is easier to read and also keeps your ideas concise for the audience. Instead of reading your slides, you’re explaining your main ideas. (Some speakers even suggest slides with no text at all, just images.)

Choose your best stories.

According to storytelling expert Matthew Luhn, people will only remember about 5% of the facts you tell them after ten minutes. However, if you wrap those facts in a story, research has shown that people could remember up to 65% of your important info.

The best keynote presentations are really just a series of good stories. 

This is why Eric O’Neill, a cybersecurity speaker, doesn’t even use slides in his keynotes. His presentations weave stories with pertinent details to entertain the audience.

Practice and prepare well in advance.

No matter what the length of your keynote, you will need to practice months in advance to prepare for a keynote.

TEDx suggests starting six months before the event date. Other practitioners, like Nancy Duarte (author of Resonate), suggest spending 30 hours writing a keynote, 30 hours working on slides, and another 30 hours practicing the talk.

So, how long should your keynote speech be? While the length depends on the event itself, you should always prepare more content than you will ever use.

If you would like to learn more about keynotes, read

How To Be A Good Keynote Speaker

How to Use Personal Stories to Create Oscar-Winning Films and Successful Sales Pitches

How Do You Become a Keynote Speaker?

How Do You Introduce A Keynote Speaker?