Google is moving the goalpost for what counts as a billable display impression inside Campaign Manager 360 and Display & Video 360. Rather than logging a charge when ad code starts running, the platforms will bill only when the creative files have finished downloading to the browser. The switch lands in February 2027, according to a help center update last refreshed on August 21, 2026.
Why this is more than a definition
Under the current on-download method, an impression is recorded when the ad’s code payload begins executing in the browser or app. The new begin-to-render standard is stricter: it counts only once the creative assets — images, HTML5 bundles, video files — have completed download. Google says this makes billed impressions “more likely to have had a tangible opportunity to be seen” and expects “a slight decrease in overall billed impression volume.”
That gap is the population leaving your invoice. Think of a reader closing a tab, a slow mobile connection dropping a heavy creative, or an ad slot collapsing before the files arrive. Those incomplete downloads currently count. From February 2027, they won’t.
Three ways the numbers shift
- CPM: If spend stays flat while billed impressions fall, effective CPM rises arithmetically.
- CTR and conversion rates: Ratios built on impressions go up as the denominator shrinks.
- Reconciliation: The gap between CM360 and third-party ad servers may narrow or widen, and IAB’s 10% discrepancy threshold becomes the place to watch.
The awkward timing question
Google scheduled a nearly identical move for September 2025, and again described CM360 changing during 2025. The February 2027 notice doesn’t explain whether those earlier plans moved invoices or changed only reported figures. For agencies comparing cost per thousand impressions across the break, that distinction matters a lot.
On the sell side, AdSense and Ad Manager publishers move to begin-to-render counting on February 17, 2027. Ezoic has already changed its ad serving to render units only as they approach the viewport. That cut display impressions by about 25% and lifted viewability to 87% — a preview of how much ad supply can move when rendering becomes the billing trigger.
What to do now
Google says no action is required. For performance teams, that’s an invitation, not a conclusion.
Treat February 2027 as a break in your time series. Rebase your CPM, CTR and viewability baselines before the change, document which measurement basis applies to each invoice, and agree internally on how you’ll compare pre- and post-switch months.
Also review direct buys where CM360 is the controlling measurement. If your publisher or verification vendor counts differently, a small billing change can surface as a reconciliation issue.
Source: PPC Land
