Cookie consent banners add a real loading cost, with good-LCP down 3.7 points on mobile. Yet the sites that run them pass Core Web Vitals more often overall, because consent tools cluster on better-built sites.
Source: PageSpeed Matters analysis of 9.5 million origins with CrUX field data, mobile 75th percentile, mid-2026.
On the one metric a banner actually touches, banner sites are behind. That 3.7-point gap is the honest, tool-attributable cost.
Source: PageSpeed Matters, mobile 75th-percentile field data, mid-2026. Values shown as with-banner versus without.
A well-built consent tool touches loading, not responsiveness. The INP gap is the site-quality confound in plain view.