Podcast Stats Soundbites: How Popular is MP3 vs M4a for Podcasting?

Data. We love it. It’s why we built our podcast stats platform the way we did, and why we were so excited to be the first IAB Certified podcast host. We also have the largest podcast directory in the universe, at 800,000 and climbing. We like to share some of the interesting podcast stats tidbits we come across. So, in this edition of Podcast Stats Soundbites, we’ll dive in to a question we hear pretty frequently: how popular is MP3 vs. M4a for podcasting? Here’s the data!

Latest episode by format for podcasting all time (~800k shows):

Latest episode by format for podcasting all time (~800k shows):

Podcasts which released at least one episode in 2019 (~360k shows):

Podcasts which released at least one episode in 2019 (~360k shows):

 

At first glance, and in popular opinion, it appears more podcasters have opted for the m4a format over mp3 in recent years. But as we dig deeper into the data, you’ll see that’s not the case: m4a adoption has been relatively constant at ~5% market share since we started monitoring it in 2007.

For some context, though, keep in mind that m4a format has had its share of limitations, most notably lack of device support. These limitations still exist, but in less that 1% of devices currently available. What’s that mean for podcasters? It means less than 1% of your audience might run into an issue with m4a. 

Which got us wondering: what’s driving the recent surge in popularity for m4a? When you dig in, it appears to be Anchor.fm, a free podcast platform that tries to make podcasting simpler by–among other things–forcing all podcasters to use m4a.

Anchor.fm, which uses a “freemium” model, appears to have chosen m4a due to it’s small file sizes. If we remove Anchor.fm users as an outlier, true m4a usage is much lower. As a podcaster, when you choose to edit your audio and maintain the quality of the audio yourself (excluding anchor.fm) the distribution is much different

Percentage of m4a usage in the podcasting market:

Percentage of m4a usage in the podcasting market

The reason we removed Anchor is that they have a higher than average turn-over and quite a low show success rate. In the past 3 months, only 12% of podcasts with 10 or more episodes (~13,500) have produced new episodes. In other words, nearly 9 out of 10 podcasts on Anchor.fm either leave the service or abandon their podcast altogether.

Given such a high churn rate, we thought it’d make sense to look at m4a adoption without Anchor.fm. When you you remove them, m4a adoption is till only 4.3%.

Other formats

More interesting is the “other” formats. Video and open source formats, such as mp4 and oga/ogg is now less than 1%.

What’s this mean for podcasters?

This indicates that podcasting is now almost exclusively audio, and that audio production is primarily in mp3 other than about 4% who actively choose m4a, and another 20% who do not actively choose a format (or, at the very least, have the choice made for them.)

Bonus Stat: Blubrry Podcast Hosting customers’ popular formats match the industry

For reference, our podcast hosting customers reflect the rest of the industry.

Blubrry Podcast Hosting customers’ popular formats match the industry