Floor Price
The minimum CPM a publisher will accept for an ad impression in a programmatic auction.
What is a Floor Price?
A floor price (also called a price floor or minimum bid) is the lowest CPM a publisher is willing to accept for an ad impression. In programmatic auctions, any bid below the floor price is rejected, and the impression either goes to a higher bidder, passes back to another demand source, or goes unfilled. Floor prices are set in the publisher's ad server or SSP configuration and serve as a quality control mechanism to prevent inventory from being sold at unprofitably low rates.
Floor prices can be set globally (applying to all inventory), per ad unit, per geography, per device type, or even per advertiser category. Advanced publishers use dynamic floor pricing that adjusts automatically based on historical bid data, time of day, and other variables.
Why It Matters for Publishers
Floor prices are one of the most powerful revenue optimization levers available to publishers. Set them too low, and you're leaving money on the table by accepting cheap bids when advertisers would have paid more. Set them too high, and you'll reject viable bids, tanking your fill rate and potentially earning less overall despite higher per-impression revenue.
The optimal floor price varies by inventory segment. Your above-the-fold, US desktop traffic might support a $3 floor, while below-the-fold mobile traffic from developing countries might need a $0.30 floor. Granular floor price management can increase total revenue by 10-25% compared to a single global floor.
Tips for Optimization
- Start conservative and increase gradually: Begin with floors at 50-60% of your current average eCPM and slowly raise them while monitoring fill rate. This minimizes risk.
- Use dynamic floor pricing: Tools like Google's Unified Pricing Rules or third-party solutions can automatically adjust floors based on real-time data, outperforming static floors.
- Segment floors by geography: US, UK, and other Tier-1 traffic supports much higher floors than traffic from developing regions. Set geo-specific floors to optimize each segment.
- Monitor fill rate impact: Track fill rate alongside floor price changes. A 20% eCPM increase is great, but not if fill rate drops 40%. Aim for the price-volume combination that maximizes total revenue.
- Review and adjust monthly: Advertiser budgets and demand fluctuate seasonally. Floors that work in Q4 may be too high in Q1 when budgets reset.