When you weigh push ads vs popunder ads, the real question isn't which format is inherently better — it's which one fits the audience and the offer sitting in front of you. Push ads generally convert better on a per-impression basis because the person seeing the notification already opted in to receive it. Popunder ads generally win on raw volume and cost, because they don't require an opt-in at all and can run on almost any site, in almost any browser, at a very low CPM.
That trade-off — quality of intent versus sheer reach — is the whole comparison. A finance offer that needs a qualified lead behaves differently under each format than a sweepstakes campaign that just needs clicks. Below is how the two actually compare, and how to decide which one deserves your next test budget.
| Format | Best for | Typical cost | Main trade-off |
|---|---|---|---|
| Push ads | Opt-in audiences, retargeting, subscription and finance offers | Mid-to-high CPC or CPA; smaller volume | Reach is capped by your subscriber list and by browser support, which has been shrinking |
| Popunder ads | High-volume, low-cost campaigns; dating, software downloads, sweepstakes | Very low CPM, often the cheapest format available | Weaker intent signal, lower viewability, and a real risk of ad-blocker or browser interference |
Neither number tells the whole story on its own — a cheap popunder impression that never converts costs more per sale than an expensive push notification that does. The sections below explain why.
Push ads
Push ads are browser notifications a user agreed to receive after clicking "allow" on a subscription prompt. Once someone opts in, you can send them a notification-style ad that appears on their desktop or lock screen, independent of whether they're currently browsing your site. That opt-in step is the format's defining feature: every recipient chose, at some point, to hear from that particular publisher or ad network, which is a stronger starting signal than almost any other display format offers.
That intent signal is why push tends to perform well for offers that need a real decision from the user — signing up for a trial, registering with a broker, completing a form. The audience has already demonstrated some willingness to engage, so the message doesn't have to fight for attention from a cold start. It's also reusable: a subscriber list can be messaged repeatedly, which makes push a genuinely retention-oriented channel rather than a one-shot impression buy.
The downside is reach. Building a push subscriber base takes time and traffic, and it doesn't scale as fast as a network-wide popunder buy can. Browser support has also been tightening — Google has been rolling out stricter permission prompts in Chrome that make it harder for sites to win push opt-ins in the first place, and Safari on iOS only added web push support in 2023 with its own restrictions (WebKit blog). None of that kills the format, but it means push inventory is smaller and slower to grow than popunder inventory, and campaigns need patience to build a list worth advertising to.
Popunder ads
A popunder opens a new browser window or tab behind the one the visitor is actively using, so they see it only when they close or minimize the active window. There's no opt-in step — the ad fires the moment a visitor lands on a page carrying the tag, on essentially any browser that hasn't actively blocked it. That's what makes popunder inventory so much larger and cheaper than push: every visitor is a potential impression, not just the ones who subscribed.
That volume is the format's real strength. For offers where the funnel is short and the value per conversion is low — software downloads, sweepstakes, dating signups — popunders can generate a lot of cheap traffic fast, which is exactly what those campaigns need to find a profitable angle through testing. The cost per impression is typically the lowest of any major ad format, which gives advertisers room to test broadly before narrowing in on what works.
The honest downside is traffic quality. A popunder interrupts the browsing session by definition, and the visitor didn't ask for it the way a push subscriber did. That shows up as lower viewability and weaker engagement once someone actually looks at the ad — a dynamic the industry has flagged directly. The Coalition for Better Ads, an industry group backed by Google, IAB, and others, lists pop-up ads (the family popunders belong to) among the small number of formats that consistently exceed the annoyance threshold its own consumer research established for both desktop and mobile (Better Ads Standards). Google has also penalized sites that rely on intrusive interstitials in mobile search rankings since 2017, which pushed some publishers away from the format entirely (Google Search Central). Popunders also get caught by ad blockers and popup blockers more often than notification-style formats, which quietly erodes the delivered volume you're actually paying for.
Push ads vs popunder ads: how to choose
Match the format to the offer's funnel length and the audience's intent, not to whichever CPM looks lower on a rate card. If the offer needs a real decision — a signup, a deposit, a form completion — push ads are worth the higher cost per impression because the audience arrives warmer. If the offer is impulse-driven and the funnel is a single click, popunders' volume and low cost usually produce more conversions for the same budget, even with a lower conversion rate per impression.
Budget stage matters too. Early in testing, when you're trying to find a profitable angle at all, popunder volume gets you signal faster and cheaper. Once you know an offer converts, push traffic — especially retargeted to your own subscriber list — tends to extend the life of that campaign at a better margin, because you're not paying to reach cold strangers every time. Running both in parallel, one for volume and one for qualified retargeting, is a reasonable way to cover both jobs rather than picking one format permanently. A network like Adsy runs push and popunder inventory side by side, so testing both against the same offer doesn't require managing two separate platforms.
Whichever you choose, judge it against one number, not the rate card: cost per conversion, not cost per impression. A cheap popunder that never converts is more expensive than an expensive push notification that does.
FAQ
Do push ads or popunder ads have a higher conversion rate?
Push ads typically convert at a higher rate per impression because the audience already opted in. Popunders usually convert at a lower rate but at much higher volume and lower cost, which can still produce more total conversions for offers with a short funnel.
Are popunder ads bannable or against browser policy?
Popunders aren't illegal, but they're commonly blocked by browser popup blockers and ad-blocking extensions, and Google has penalized sites using intrusive interstitials in mobile search since 2017. Check your traffic source and creative rules before running them.
Can I run push and popunder campaigns for the same offer at once?
Yes. It's a reasonable way to test an offer for cost per conversion across two very different audience types — cold, high-volume traffic through popunders and warmer, opted-in traffic through push — without committing to one format before you have data.
Why is push ad inventory smaller than popunder inventory?
Push requires a visitor to actively opt in to notifications, which is a higher-friction step than simply loading a page. Building that subscriber base takes time, and tightening browser permission prompts have made opt-ins harder to win, which keeps push volume below popunder volume.
Which format is better for a low-budget test?
Popunders are usually the better starting point for a low budget because the cost per impression is lower and you can gather conversion data faster. Once you've confirmed the offer converts, shifting some budget to push can improve margin on the audience you've already proven works.
Conclusion
Push ads and popunder ads solve different problems: push trades reach for intent, popunders trade intent for reach and cost. Neither format is a universal answer to "which converts better" — the answer depends on how much the offer needs a qualified decision versus how much it needs cheap volume to find its angle. Test both against the same offer and read the results against cost per conversion, not the sticker price of the impression.
Key takeaways
- Push ads convert better per impression because the audience opted in, but volume is limited by subscriber list size and browser support.
- Popunder ads offer the lowest cost per impression and the highest volume, but weaker intent and viewability.
- Short-funnel, impulse offers usually favor popunder volume; longer-decision offers usually favor push's warmer audience.
- Popunders face real headwinds from ad blockers and search-engine interstitial penalties.
- Judge either format by cost per conversion, not cost per impression, and consider testing both before committing budget to one.
