Advertisers should be allocating 20% of their marketing budget to audio campaigns to maximise profits, according to a new study by Radiocentre, the trade body for commercial radio.
The High Gain Audio research, unveiled during a presentation at Radiocentre’s Tuning In event in London on 23 September, reveals that both broadcast radio and digital audio outperform the all-media average on profitability, in both the short and long term. The full report will be published later this year.
The study is a follow-up to the 2013 Radio: The ROI Multiplier report, which found that radio delivers an average ROI of £7.70 for every £1 spent, second only to TV. Mark Barber, planning director at Radiocentre, said that Radiocentre wanted to run an updated study to see if radio’s performance has held strong in the last decade or so.
Barber argued the landscape had shifted rapidly in that time, thanks to more people listening via IP-connected devices. Total commercial listening is up 23% since 2018. Barber specifically pointed out the rise of smart speakers, which have gone from being in 0% of households in 2013 to 48% in 2024.
Barber said: ‘Commercial audio in 2025 is in a very healthy position. Yet despite all the positive momentum in terms of audience growth and cross-platform audio advertising and operating, multi-platform audio ad revenue has been growing at a much slower rate.’
Audience grew by 5.2% between 2023 and 2024, yet ad revenue only increased by 1.8%.
Drawing on Thinkbox’s Profit Ability 2 report, alongside a new WPP ‘multi-platform audio’ dataset, the new study isolated the effects of broadcast radio and digital audio across brands that invest significantly in both formats.
It found that audio delivers short-term ROI (within three months) 32% higher than the average channel, and long-term ROI (within two years) 21% higher. When split out individually, both formats prove their strength:
- Digital audio (streaming, podcasts and radio listening via IP devices) delivers £5.20 in long-term profit return for every pound spent, and £2.70 in the short term.
- Broadcast radio (linear radio listened via non-IP devices) delivers £5 in long-term profit and £2.30 in the short term.
Both comfortably exceed the all-media averages of £4.11 (long-term) and £1.87 (short-term).
As the 2013 research did, High Gain Audio also analysed marginal ROI, or the return on the very last pound spent. Modelling scenarios to maximise audio spend showed that brands could more than double their current investment in both formats before reaching the breakeven point. Pushing audio’s share of the media mix to 20–24% could increase overall campaign ROI by up to 8.2%.
WPP’s Jane Christian, EVP of analytics at Choreograph, who led the modelling, highlighted the practical implication: ‘The key point is that there is headroom, profitable headroom, for both forms of audio. That is absolutely still true when we break out the effects into digital audio and broadcast radio.’
To help advertisers put these findings into practice, the presentation outlined three guiding principles:
- Set audio at roughly 20% of the media mix as a realistic, evidence-backed target for profitable growth.
- Treat broadcast and digital as partners. Combined strategies drive stronger results than treating them in isolation.
- Update MMM approaches to measure the distinct contributions of both broadcast and digital audio accurately.
Barber said: ‘High Gain Audio’s key takeaway is clear: multiplatform audio advertising is underinvested, with both broadcast radio and digital audio individually exceeding the all-media profit ROI average.
That’s why, based on the outputs from this analysis, and acknowledging that each individual media campaign will have its unique set of dynamics to accommodate, we’re advocating that, to benefit more fully from its amplification effect on overall campaign ROI, advertisers consider setting a new horizon where 20% of total media spend is allocated to audio.’
Main image by Eric Nopanen on Unsplash
