Glossary
What is Fill rate?
Also called: fill
Fill rate is the share of ad requests that return an ad: impressions ÷ ad requests. 8,500 impressions from 10,000 requests is 85%.
हिंदी में पढ़ेंFill rate tells you how much of the inventory you offered was actually sold. Google Ad Manager calculates total fill rate as total impressions divided by total ad requests. AdMob uses different terms, match rate and show rate, for similar ideas.
Requests usually go unfilled for one of three reasons: no buyer wanted that visitor, country or ad size; every bid was below your floor; or the bids arrived too late. An unfilled slot can show a house ad, your own promo, or stay empty.
A 100% fill rate is not the goal. A floor that turns away a few cheap bids can lower fill and still raise total revenue, because the impressions that do sell earn more. Split fill rate by country, device and ad size to find where demand is weak. One weak segment often points straight to the cause.
Example
A sidebar slot sends 10,000 ad requests in an hour and 8,500 return a paid ad. Fill rate is 8,500 ÷ 10,000 = 85%, leaving 1,500 requests unfilled.
Why it matters to publishers
Fill rate shows whether lost revenue comes from too few buyers rather than low prices, and a weak segment points you to the cause.