Google Ad Manager To Change How It Counts Display Ad Impressions

Google is preparing to change how its Ad Manager and AdSense platforms count display advertising impressions, moving from a count-on-download method to a begin-to-render standard from February 17, 2027.

The shift means display ad impressions will only be recorded once an ad creative has successfully loaded and started to render on a user’s device, rather than when the ad merely begins downloading. The change is expected to result in lower reported impression numbers for publishers.

What is changing

Google Ad Manager and AdSense currently use a count-on-download (COD) methodology for display inventory. Under this approach, an impression is counted when the ad server responds to a request and the creative asset begins downloading to the user’s device.

The new begin-to-render (BTR) methodology sets a higher bar. An impression will only be counted once the creative has fully loaded and begun rendering on the device, meaning the user has a greater likelihood of actually seeing the ad.

The change applies to display banner inventory across web, mobile web and connected TV (CTV). It does not affect other inventory types, as Google’s native, app and video ad formats are already BTR-compliant.

Why the change is happening

The Interactive Advertising Bureau (IAB) and the Media Rating Council (MRC), in partnership with other industry bodies, have progressively updated standards for how impressions should be measured.

Those standards have evolved over time – from counting when an ad is served, to counting when it begins downloading, and now to counting when it begins rendering. BTR is the current industry-standard methodology recommended by the IAB and MRC.

Google has framed the move as an alignment exercise. By adopting BTR for display inventory, Ad Manager will use a unified counting methodology across all its inventory types, matching the approach already used by demand-side platforms and third-party measurement providers.

The company has also pointed to operational benefits for publishers, noting the change should reduce discrepancies between Ad Manager impression counts and those reported by buyers or third-party measurement vendors. Publishers currently need to buffer their COD campaigns to deliver against BTR terms, a workaround that would no longer be necessary.

Expected impact on publishers

Google has warned publishers to expect a decrease in total reported display impressions after the transition. Under COD, impressions are counted for ads that begin loading on a page but may never fully render – for example, if a user navigates away before the ad finishes loading. Those impressions will no longer be counted under BTR.

The company has told publishers that no action is required on their part. The switch will take effect automatically on February 17, 2027.

How publishers can prepare

Google has recommended that Ad Manager publishers run reports to estimate the potential difference between their current COD and future BTR impression counts.

Publishers can do this by creating an interactive report in Ad Manager that compares “Ad server impressions” (currently using COD) against “Ad server begin to render impressions.” Google has advised using a historical report with a start date after August 12, 2026, for a clearer picture.

The relevant report dimensions include demand channel, inventory format, inventory type (expanded) and device category. Google has indicated that additional BTR metrics for Ad Exchange and yield group impressions will be made available in the near future.

After February 17, 2027, and a brief ramp-up period, standard impression metrics will align with BTR impression metrics in reporting.

Creative and technical considerations

Google has urged publishers to optimise their ad creatives to improve asset downloading and rendering speeds. Poorly optimised creatives that consume excessive network or CPU resources may be disabled by Chrome under its heavy ad criteria, which could prevent ads from rendering and therefore from registering impressions under the new methodology.

Publishers using lazy loading and lazy rendering settings should also review their configurations. Lazy rendering directly affects BTR measurement because it determines when creative assets start rendering in the browser.

Raising the renderMarginPercent or fetchMarginPercent values causes assets to render earlier in the user experience, which could improve BTR impression counts. However, Google has cautioned that these settings also increase resource demands on the publisher’s network and the end user’s device, and publishers should weigh the trade-offs before making adjustments.

Accreditation unchanged

Google has confirmed that Ad Manager will continue to retain MRC accreditation for display, video and rich media creatives within desktop, mobile web and mobile application environments following the transition.

Publishers with questions about the change have been directed to contact their Account Manager or Ad Manager Support.

Last Updated on September 2, 2026 by Nick Ross