Ad fill rate
A publisher's yield gauge — every unfilled request is inventory that earned nothing.
- Measures
- requests answered with a paid ad
- Whose metric
- publishers, ad-supported apps
- 100% fill
- rarely the goal
- Pairs with
- CPM, viewability
Forms & parts of speech
What fill rate tells a publisher
Every time a page or app asks the ad stack for an ad, that is a request. Fill rate is the share of those requests that come back with a paid impression instead of a blank or a house ad.
A low fill rate means demand is not showing up for that inventory — wrong price floor, weak demand partners, or audience advertisers do not want. The request happened; the revenue did not.
Why 100% is not the target
You can hit a high fill rate by dropping your price floor until almost anything wins — but you fill at pennies. Yield is fill rate times the price you fill at, so chasing fill alone can lower total revenue.
The real lever is the trade-off. Raise floors and fill drops but average CPM rises; lower them and fill climbs but CPM falls. Publishers tune for revenue per thousand requests, not fill for its own sake.
The 8 points of lost fill were low-value impressions; the publisher earned more by filling fewer requests at a better price.
Benchmarks
Fill-rate norms vary by format, geography, and floor strategy. There is no portable benchmark — tune fill against the CPM you achieve.
Ranges are illustrative; every published figure is cited from a named public source or labelled “RGM analysis.”
Synonyms & antonyms
Synonyms
Antonyms
Usage trends
Search interest for this term over the last five years:
Common questions
- What is a good ad fill rate?
- It depends on inventory and floors — there is no universal number. A high fill rate at a low CPM can earn less than a lower fill rate at a strong CPM.
- Why is my fill rate low?
- Common causes are price floors set above what demand will pay, too few demand partners, or audiences advertisers are not bidding on.
- Fill rate vs viewability?
- Fill rate is whether a paid ad was returned; viewability is whether a served ad was actually seen. Both feed real yield.
Related tools & calculators
Resources & people to follow
- referenceGoogle Ad Manager Help — fill rate
- referenceIAB — programmatic measurement guidance
Curated, non-competitor resources verified per term.