Financial Metrics
Fill Rate
The percentage of available ad requests (avails) that are successfully filled with a paying advertisement by an automated ad server.
What is Fill Rate?
Fill Rate measures what fraction of available inventory actually gets monetized. A podcast feed that generates 1,000,000 ad requests per week and fills 800,000 of them has an 80 percent fill rate. The remaining 20 percent is either left silent, replaced with house promos, or filled with PSAs — all of which yield zero revenue.
Fill rate is a function of demand, pricing, and inventory quality. A publisher with a high floor price and strong demand can run at 95+ percent fill; a publisher whose floor is too high or whose audience is niche may struggle below 60 percent. Programmatic platforms rely on SSP integrations and real-time bidding to lift fill rates, but the fundamental economics are always shaped by whether buyers want the inventory on offer.
Why it matters
A crucial metric for streaming and digital publishers; a persistently low fill rate indicates poor inventory monetization and severe revenue leakage.
Related terms
- Gross Revenue— The total, unadjusted top-line income generated from advertising sales before deducting agency commissions, operational costs, or taxes.
- CAC (Customer Acquisition Cost)— The total combined sales, operational, and marketing expenditure required to successfully win a new advertising client.
- Cost Per Acquisition (CPA)— An advertising pricing model where the advertiser pays only when a specific desired action (a sale, a click, a form fill) is completed.
- Cost Per Completed View (CPCV)— A digital video and advanced TV metric where the advertiser only pays if the video advertisement plays entirely to completion.