Fill Rate: What It Is and How to Improve It

Ever wondered why some ad slots stay empty while others are always packed? That’s the fill rate at work. In plain terms, fill rate is the percentage of ad requests that actually get a ad back. If you serve 1,000 requests and only 700 get ads, your fill rate is 70%.

A high fill rate means more impressions, more clicks, and ultimately more money. Low fill rates waste inventory and can hurt your bottom line. The good news? You can lift your fill rate without spending a fortune.

Why Fill Rate Matters

First off, advertisers look at fill rate when they decide where to place their budget. A site with a 95% fill rate looks reliable, while a 50% rate raises red flags. Second, most ad networks pay per impression, so every empty slot is lost revenue. Finally, a solid fill rate improves user experience – fewer blank spaces keep visitors engaged.

Quick Ways to Boost Your Fill Rate

1. Use Multiple Ad Networks
Relying on a single network is risky. If that network can’t fill a request, you lose the impression. Adding a secondary or tertiary network gives you backup coverage and raises overall fill.

2. Optimize Ad Formats
Some formats, like native or video ads, have lower demand in certain markets. Offering a mix of banner, native, and video options lets more advertisers match their creative to your inventory.

3. Clean Up Your Site Speed
Slow pages cause ad requests to time out, which drops fill rate. Compress images, use a CDN, and keep scripts lean to keep requests fast.

4. Target High‑Demand Geos
Advertisers prize traffic from the US, UK, Canada, and Australia. If your audience is mostly from low‑value regions, consider geo‑targeting to prioritize high‑value requests.

5. Implement Header Bidding
Header bidding lets several demand sources bid on the same impression simultaneously. It levels the playing field and often results in higher fill and better CPMs.

6. Keep Your Inventory Fresh
Stale or low‑quality content gets ignored by advertisers. Regularly update blogs, add new product pages, and keep the site lively to attract fresh demand.

Remember, the goal isn’t just a higher number; it’s a higher number that brings real money. Track your fill rate daily, test one change at a time, and watch the metrics move.

Ready to crank up your ad earnings? Start with one of the tips above, measure the impact, and keep iterating. A better fill rate is just a few tweaks away.