What are Core Web Vitals and do they affect your rankings?
Three loading and stability scores, with an honest read on how much they matter.
Core Web Vitals are three metrics Google uses to describe how a page feels to use. They are a real but small ranking input and a large conversion input, so fix them for revenue reasons and take the ranking benefit as a bonus.
The three metrics
- Largest Contentful Paint (LCP) measures loading. Google's web.dev guidance says LCP should occur within 2.5 seconds of when the page starts loading.
- Interaction to Next Paint (INP) measures responsiveness, how fast the page reacts when someone taps or clicks. Google's threshold for good is 200 milliseconds or less. INP became a stable Core Web Vital in 2024, replacing First Input Delay.
- Cumulative Layout Shift (CLS) measures visual stability, the annoyance of a button moving as you reach for it. Google says pages should maintain a CLS of 0.1 or less.
Google evaluates these at the 75th percentile of page loads, measured separately for mobile and desktop. That last detail matters: your desktop score can be fine while mobile fails.
The honest read on rankings
They are a tiebreaker, not a lever. A fast page with weak content will not outrank a slow page that answers the question better. If your Vitals are bad and your rankings are flat, the Vitals are probably not the reason. If two comparable pages compete, the faster one has an edge.
The reason to fix them anyway
Conversion. A slow, jumpy page loses people before they read the offer, and that cost is immediate and measurable in your own analytics. The usual culprits are the same every time: oversized uncompressed images, too many third party scripts, especially chat widgets and tag stacks, fonts that block rendering, and images or ads with no reserved height, which is what causes layout shift.
We deal with these during design and build rather than bolting on a speed plugin afterward, because most of the damage is architectural.
Related: What is technical SEO and what does it cover?, Will my website be mobile-friendly?, Does LevelUp Digital build websites on HubSpot CMS?, How Adaptive UI/UX Can Skyrocket Your Conversion Rate