Definition
"Interstitial" means "in the space between". The format covers the whole viewport for a moment the visitor expected to wait anyway: a page change, a level clear, a download starting. Because it is served on the publisher's own page, it is not subject to popup blocking, and because it has a close control it is compatible with Google's Better Ads Standards when shown on page transitions rather than on page load.
How interstitial ads work
- The publisher's script detects a transition event, for example a click on an internal link.
- The script requests a full-screen creative matching the visitor's GEO, device and orientation.
- The creative covers the viewport; a close control appears immediately or after a short countdown.
- The visitor clicks through or closes and continues to the destination page.
- The impression is billed at the CPM bid.
Creative requirements
Interstitials are the one display format where the creative must exist in both orientations: a portrait image of 1080×1920 for phones and a landscape image of 1920×1080 for desktop. Networks also accept a landing URL instead of an image, in which case the destination page is shown inside the full-screen frame, the same mechanic as a popunder but in the foreground.
Who uses interstitials
Advertisers who want the pop-style full attention with a branded creative in front of it: iGaming and sports betting promotions, VPN and utility installs, e-commerce sales events. Publishers of games, tools and streaming sites use them at transition points where a banner would be ignored.
Related terms
| Term | Relation | Where defined |
|---|---|---|
| Popunder ads | Background full-page alternative | Term page |
| Banner ads | In-slot display alternative | Term page |
| CPM | Pricing model | Term page |
| Video ads | Often served in the same slot | Term page |
FAQ
Are interstitial ads allowed by Google?
Yes, when shown at a transition the user initiated and with a close control. Interstitials that appear on page load or block content on mobile without a close button fall under the Better Ads Standards and are penalized.
What is the difference between an interstitial and a popunder?
An interstitial is shown in the foreground, inside the publisher's page, at a transition; a popunder opens a new tab behind the current page. Both are full-page and priced per thousand impressions.
What creative sizes do I need?
A portrait 1080×1920 image for mobile and a landscape 1920×1080 image for desktop, or a landing URL the network frames full-screen.