The cost of podcast advertising dropped in February compared to an unusual January spike. This according to AdvertiseCast, the Libsyn-owned ad marketplace. The average CPM of a 60-second spot was $23.41 in February, down from a two-year high of $25.40 in January.
Podcast advertising rates are measured in cost per thousand impressions (CPM), as in other types of digital advertising. within that framework, variables create several CPM rats. The main influencers are length of ad (categorized with traditional 30-second or 60-second, despite many host-read ads departing from those restrictions), and size of the audience.
The AdvertiseCast pricing info was based on reporting data for 2,755 podcasts. In the illustration below, the black line represents the average cost for a thousand 60-second spots across shows of varying audience sizes. The bigger the audience, the more discounted the CPM price.