3/4ths (77.0%) of Top 100 Podcasts have ads, but only 1/4th (28.4%) of All Podcasts* have ads…

We estimate that about 7,000 podcasts have ads.

If you’ve listened to a podcast lately, you might have heard an ad for ZipRecruiter or Squarespace. But just how many podcasts actually have ads?

Magellan has the world’s best technology for tracking ads and advertisers in podcasts. Magellan uses our advanced machine learning algorithm to recognize ads in podcasts. Every week, we track the top 2,000 podcasts in the U.S. as ranked by Apple Podcasts — this is how we derived our top 100, 400 and 2,000 metrics. Within 10 minutes of an episode being published to an RSS feed, our software downloads it and recognizes the ads.

All in all, Magellan analyzes over 4,000 episodes every week, helping brands verify ad placements and helping podcast publishers target advertisers. Magellan has tracked and recorded over 100,000 unique podcast ads in the last 12 months.

For this analysis, we answered the question: how many podcasts in the long tail actually have ads?

Cool. So how many podcasts have ads?

How we calculated the number of all podcasts with ads

We began with the 24,505 podcasts that have ranked anywhere (top 400 in any category) in Apple Podcasts’ top charts in the past year and have published in the last month (*All Podcasts). We’ve previously analyzed episodes from 4,768 of those podcasts — so we focused on the remaining 19,737.

We downloaded an episode of each of those 19,737 shows and randomly selected 5% (971 episodes) to analyze.

Like many machine learning algorithms, Magellan assigns a probability to each segment of a podcast to answer the question — is this segment an ad? Episodes fall into three categories. Two categories are easy to evaluate:

• 5% of our sample (49 episodes) definitely had ads
• 47% of our sample (456 episodes) definitely did not have ads

That left 48% of our sample (465 episodes) that had segments Magellan thought could be ads. With the help of pizza, our team reviewed a subset of these episodes to determine that 34% of our sample (155 episodes) contained “real” ads.

I don’t care about the details. How many podcasts have ads?

Ok, so now we’re ready to calculate an estimate for how many podcasts have ads.

Out of the 4,768 podcasts that we’ve previously analyzed, 2,787 feature ads.

So the question is — how many of the remaining 19,737 podcasts that have ranked on Apple Podcasts’ top charts in the past year and published episodes in the last month feature ads? Remember, we determined that 204 podcasts (49 + 155) out of the 971 in our sample had advertisements. That means about 21% of podcasts in that set — or 4,167 podcasts — have ads.

In total, we estimate that 6,954 podcasts have ads. Since we were only sampling podcasts, we could still be wrong — but we can say that with 90% confidence that between 5,914 and 7,994 podcasts have ads.

Caveats & ways we could improve this analysis

This analysis doesn’t take pricing variations into account. That is, ads for Gillette on The Bill Simmons Podcast are probably significantly more expensive than most ads. Some podcast sponsorships may cost a total of $100/episode — others may cost $250,000 or more an episode. See the top podcast advertisers here.

There are also quite a few ways we could improve this analysis:

• There are over 500,000 podcasts available through Apple Podcasts. We could analyze podcasts that have never ranked in Apple’s charts.
• Some podcasts are repurposed radio content, and could include radio ads. We could differentiate between native, host-read ads and radio ads.
• We only sampled one episode from each podcast in our “unknown” set, and we might have gotten unlucky by finding an episode without an ad. We could sample more episodes to increase our accuracy.

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