Site speed is the collective measure of how quickly a web page's content loads and becomes interactive for visitors, assessed through metrics including Largest Contentful Paint (LCP), Time to First Byte (TTFB), Total Blocking Time (TBT), and Speed Index. Google confirmed site speed as a ranking signal in 2010, and the importance increased when Core Web Vitals became part of the page experience ranking system in 2021. Practically, a one-second improvement in mobile load time increases conversion rates by an average of 27% according to Google and Deloitte (2019). For WordPress sites, the highest-impact speed improvements typically come from: switching to managed hosting with server-level full-page caching, converting images to WebP format with correct dimensions and lazy loading, eliminating render-blocking JavaScript by deferring non-critical scripts, using a CDN for static asset delivery, and reducing the total plugin count — particularly plugins from vendors known for heavy asset payloads.
Glossary entry
