How this calculation works
Use request counts for a matching reporting scope. A request returning several impressions still counts once as a matched request. The complement identifies requests that returned no ad; it is not a measure of whether rendered ads were actually viewable.
Coverage = matched requests / total requests × 100%A worked example
8,000 matched requests from 10,000 requests gives 80% coverage and 2,000 unfilled requests.
Good to know
A transparent arithmetic model using your inputs. Example prices, rates and multiples are demonstrations, not benchmarks or offers. No tax, exchange-rate conversion, live account access or automatic attribution is supplied. Monetary display is rounded; calculations retain additional precision.
Reference: Google AdSense: request coverage (opens in a new tab) ↗
A request is not an impression or a page view
One page can make several ad requests. A matched request can return at least one ad, while the resulting impression count can use another reporting unit. Coverage is based on matched requests divided by total requests for the same scope.
Dividing ad impressions by page views cannot reconstruct this percentage when request counts are missing. It also cannot tell you whether an ad was visible on screen. Those questions require the appropriate reporting fields.
The ad revenue funnel separates request coverage, impressions per matched request and revenue per thousand impressions instead of treating them as interchangeable ratios.
Compare matching reporting scopes
Use the same dates, property, request type and reporting filters for the two counts. Mixing a site-wide numerator with a single-unit denominator can make an apparently extreme result that is simply a scope mismatch.
Zero matched requests with positive requests gives zero coverage. Zero total requests leaves the ratio undefined, so that input is rejected. A percentage describes what happened to those requests; it does not identify the cause of an unfilled request.
A few questions, answered
Can matched requests exceed requests?
Not for a properly matched request-level scope. The calculator rejects that combination and asks you to check the inputs.
Does 100% coverage mean 100% viewability?
No. Returning an ad and having it viewable on screen are different events and metrics.