Do 30-Second Ads Outperform 15-Second Ones?
When it comes to crafting ads that stick, one question always comes up: are 30-second spots more effective, or should we be leaning into shorter, 15-second formats?
It’s a fair question, especially as the way we engage with media continues to shift. The rise of BVOD and the boom in streaming platforms have completely changed the advertising landscape. People are consuming content differently, and their attention spans as well as and expectations, are evolving along with it.
Different ad lengths serve different purposes, and the right format depends on what you're trying to achieve. Whether it's building brand awareness, staying top of mind, or driving conversions, each spot length brings something different to the table.
The Case for TV
MNTN Research claims that on TV, longer ads often deliver stronger results when it comes to conversion. With more time to tell a story, 30-second spots can create a more emotional and memorable experience. Music, messaging, colour, and layout work together to leave a lasting impression—and that emotional connection can be key to driving long-term brand preference.
This format is especially useful when launching a new campaign, introducing a complex message, or building emotional resonance with an audience seeing your brand for the first time.
Shorter ads excel when the goal is brand recall and sustained awareness. A sharp, focused 15-second spot can cut through the noise and keep your brand top of mind, especially when people are multitasking or watching on handheld devices. Their efficiency may allow campaigns to run longer, helping brands remain visible and build a more consistent presence over time.
They also work well as follow-ups or reminders, reinforcing the message from a longer spot and maintaining visibility without overspending. Quick, consistent exposure can be enough to trigger interest or prompt action, like looking up a product or visiting a site.
What About Radio?
An interesting study from SiriusXM Media showed that 30-second audio ads perform well in terms of message association, brand sentiment, and recall. The extra time allows for emotional targeting through tone, pacing, and storytelling which made the brand seem more trustworthy, likeable, and relevant.
However, when it came to conversion, particularly in retail, 15-second audio ads came out ahead. The shorter length proved more effective for triggering immediate action.
While 15-second ads are not significantly cheaper on a per-second basis—most broadcasters charge between 65 percent and 75 percent of the cost of a 30-second spot—their overall cost efficiency can help support longer campaign durations which allows brands to maintain a consistent on-air presence. This makes radio a powerful medium for reinforcing brand cues, especially when shorter ads are used to build rhythm and repetition throughout the week.
No One-Size-Fits-All Answer
The most effective ads are those that align with the campaign objective and suit the platform they’re running on. Both long and short formats can be effective when used with intention, and in many cases, a smart mix of the two, across a variety of platforms delivers the strongest results.
Research from System1, found that allocating just 11% of a media budget to radio can double overall campaign effectiveness, significantly increasing brand awareness and doubling brand trust compared to campaigns without radio. Further insights from Analytic Partners highlight that sustained creative and media support amplify cross-channel impact. Notably, combining radio with digital, social, and search media was shown to increase ROI, reinforcing the value of integrated strategies.
However, it’s important to recognise that effectiveness doesn’t just depend on choosing the right ad length or placement. More critical is how clearly the message is communicated, how well it’s structured, and above all, how creatively it resonates with the audience. According to Kantar, creative quality accounts for nearly 50% of media impact, outweighing the role of reach or frequency of exposure.
With the right creative in place, Brodcast MAP's media planning and analysis tools, combined with AudioNET’s Dispatch and Verification will streamline your media trading. For more information on how we can support your next campaign, contact Broadcast MAP and AudioNET.