<b>98% fill rate is not the goal. It often means you're underpricing.</b>

<b>98% fill rate is not the goal. It often means you're underpricing.</b>

Fill rate = % of ad requests that return a paid ad. Near-100% fill usually means floors set too low — you're accepting every cheap bid.

Trade-off, illustrative:
— Floor $0.50 → fill 98%, avg CPM $4.10
— Floor $1.20 → fill 88%, avg CPM $5.30
— Net RPM: second wins by +11% despite 10pts less fill

Unfilled impressions earn $0, but a higher floor lifts the cleared price on everything that does fill.

So what: tune floors to maximize CPM×fill, not fill alone. ▲ +11% RPM from 'worse' fill.