Most Marketers Use Digital Audio, But ROI Questions Slow Spending Growth.

Digital audio is moving from an experimental line item toward a core part of advertiser media strategies, however marketers say the channel’s next phase of growth will depend on how well it can prove performance.

A new survey from Emarketer and Amazon Ads finds that 79% of U.S. marketers have used digital audio advertising, with adoption accelerating rapidly. Nearly 40% began advertising in the channel within the past two years. Today, 67% of advertisers include streaming audio and podcasts in their media mix — a third more than broadcast radio — signaling that digital audio is no longer treated as a niche buy.

That growing comfort is translating into spending intent. Sixty-five percent of marketers say they are likely to increase their digital audio investment over the next 12 months, including 25% who are “very likely” to do so. Nearly two-thirds (63%) rank digital audio as important to their media strategy.

Podcasts are a major driver of momentum. Emarketer projects U.S. podcasts are on track to capture an additional $1 billion per year in advertising by 2029, reflecting advertisers’ growing belief that on-demand audio can deliver incremental reach alongside more established digital channels.

Yet despite widespread participation and favorable sentiment, most advertisers are still testing rather than scaling. Nearly half of marketers surveyed say they allocate just 1% to 10% of their overall ad budgets to digital audio, with another 21% investing 11% to 20%. The gap between interest and investment points to lingering uncertainty about how digital audio performs beyond the top of the funnel.

“The number one challenge in digital audio is proving ROI,” Amazon DSP Director Chris Conetta says in the report. The analysis suggests digital audio’s growth is no longer about reach or advertiser interest — it’s about proof.

While a majority of marketers now use streaming audio and podcasts and plan to increase spending, the survey shows that measurement remains the dominant barrier keeping digital audio budgets in check. More than half of advertisers (55%) say difficulty measuring ROI is the biggest challenge preventing greater investment, making it by far the most cited obstacle in the report.

That measurement gap looms larger as advertisers push audio beyond brand awareness and into performance-driven roles. Roughly four in ten marketers say consideration and brand favorability are a primary objective for their digital audio campaigns, while more than a quarter are pursuing direct-response, ecommerce traffic, or conversion goals. Yet the report finds many advertisers still lack confidence that those outcomes can be clearly attributed to audio.

The result is a disconnect. Digital audio is widely used but rarely scaled. Emarketer frames this as a testing phase driven less by skepticism of audio itself and more by uncertainty around measurement tools and benchmarks.

Advertisers are explicit about what they want next. More robust measurement and attribution tools top the list of requested improvements, cited by 45% of respondents, followed closely by better ROI transparency and benchmarking and stronger case studies or proof of effectiveness.

Advertisers are increasingly focused on whether podcasts and streaming audio can support full-funnel objectives, not just awareness. The result is there is more pressure to resolve attribution concerns as podcasts, in particular, attract more lower-funnel expectations. Until that happens, the report suggests digital audio’s growth curve may remain uneven, expanding rapidly in adoption and intent but lagging in budget share.